Ventilator-initiated prompt or setting regarding detection of asynchrony during ventilation

ABSTRACT

This disclosure describes systems and methods for monitoring and evaluating ventilatory parameters, analyzing those parameters and providing useful notifications and recommendations to clinicians. That is, modern ventilators monitor, evaluate, and graphically represent multiple ventilatory parameters. However, many clinicians may not easily recognize data patterns and correlations indicative of certain patient conditions, changes in patient condition, and/or effectiveness of ventilatory treatment. Further, clinicians may not readily determine appropriate ventilatory adjustments that may address certain patient conditions and/or the effectiveness of ventilatory treatment. Specifically, clinicians may not readily detect or recognize the presence of asynchrony during ventilation. According to embodiments, a ventilator may be configured to monitor and evaluate diverse ventilatory parameters to detect asynchrony and may issue notifications and recommendations suitable for a patient to the clinician when asynchrony is implicated. The suitable notifications and recommendations may further be provided in a hierarchical format.

INTRODUCTION

A ventilator is a device that mechanically helps patients breathe byreplacing some or all of the muscular effort required to inflate anddeflate the lungs. In recent years, there has been an accelerated trendtowards an integrated clinical environment. That is, medical devices arebecoming increasingly integrated with communication, computing, andcontrol technologies. As a result, modern ventilatory equipment hasbecome increasingly complex, providing for detection and evaluation of amyriad of ventilatory parameters. However, due to the sheer magnitude ofavailable ventilatory data, many clinicians may not readily assess andevaluate the diverse ventilatory data to detect certain patientconditions and/or changes in patient conditions, such as ventilatorasynchrony. For example, extended periods of asynchrony can increase theamount of time patient needs to be ventilated by the ventilator.

Indeed, clinicians and patients may greatly benefit from ventilatornotifications when evaluation of various ventilatory data is indicativeof certain patient conditions, changes in patient conditions,effectiveness of ventilatory therapy, or otherwise.

Ventilator-Initiated Prompt or Setting Regarding Detection of AsynchronyDuring Ventilation of a Patient

This disclosure describes systems and methods for monitoring andevaluating ventilatory parameters, analyzing ventilatory data associatedwith those parameters, and providing useful notifications and/orrecommendations to clinicians. Modern ventilators monitor, evaluate, andgraphically represent a myriad of ventilatory parameters. However, manyclinicians may not easily identify or recognize data patterns andcorrelations indicative of certain patient conditions, changes inpatient condition, and/or effectiveness of ventilatory treatment.Further, clinicians may not readily determine appropriate ventilatoryadjustments that may address certain patient conditions and/or theeffectiveness of ventilatory treatment. Specifically, clinicians may notreadily detect or recognize the presence of asynchrony. According toembodiments, a ventilator may be configured to monitor and evaluatediverse ventilatory parameters to detect an asynchrony and may issuenotifications and recommendations suitable for a patient to theclinician when asynchrony is implicated. The suitable notifications andrecommendations may further be provided in a hierarchical format suchthat the clinician may selectively access summarized and/or detailedinformation regarding the presence of asynchrony. In more automatedsystems, recommendations may be automatically implemented.

According to embodiments, ventilator-implemented methods for detectingasynchrony are provided. The methods include collecting data associatedwith ventilatory parameters and processing the collected ventilatoryparameter data based on background trigger type, wherein processing thecollected ventilatory parameter data includes deriving ventilatoryparameter data from the collected ventilatory parameter data based on abackground trigger type. In some embodiments, the methods includedetermining that an asynchrony is implicated upon detecting that theprocessed ventilatory data breaches the one or more predeterminedthresholds. When asynchrony is implicated, the methods include issuing asmart prompt.

According to further embodiments, a ventilatory system for issuing asmart prompt when asynchrony is implicated during ventilation of apatient is provided based on a background trigger type. An appropriatenotification message and an appropriate recommendation message may bedetermined and either or both of the appropriate notification messageand the appropriate recommendation message may be displayed.

According to further embodiments, a graphical user interface fordisplaying one or more smart prompts corresponding to a detectedcondition is provided. The graphical user interface includes at leastone window and one or more elements within the at least one windowcomprising at least one smart prompt element for communicatinginformation regarding the detected condition based on a backgroundtrigger type, wherein the detected condition is asynchrony.

These and various other features as well as advantages whichcharacterize the systems and methods described herein will be apparentfrom a reading of the following detailed description and a review of theassociated drawings. Additional features are set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the technology. Thebenefits and features of the technology will be realized and attained bythe structure particularly pointed out in the written description andclaims hereof as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawing figures, which form a part of this application,are illustrative of described technology and are not meant to limit thescope of the claims in any manner, which scope shall be based on theclaims appended hereto.

FIG. 1 is a diagram illustrating an embodiment of an exemplaryventilator connected to a human patient.

FIG. 2A is a block-diagram illustrating an embodiment of a ventilatorysystem for monitoring and evaluating ventilatory parameters associatedwith asynchrony.

FIG. 2B is a block-diagram illustrating an embodiment of the asynchronydetection module shown in FIG. 2A.

FIG. 3 is a flow chart illustrating an embodiment of a method fordetecting an implication of asynchrony.

FIG. 4 is a flow chart illustrating an embodiment of a method forissuing a smart prompt upon detecting an implication of asynchrony.

FIG. 5 is an illustration of an embodiment of a graphical user interfacedisplaying a smart prompt having a notification message.

FIG. 6 is an illustration of an embodiment of a graphical user interfacedisplaying an expanded smart prompt having a notification message andone or more recommendation messages.

DETAILED DESCRIPTION

Although the techniques introduced above and discussed in detail belowmay be implemented for a variety of medical devices, the presentdisclosure will discuss the implementation of these techniques for usein a mechanical ventilator system. The reader will understand that thetechnology described in the context of a ventilator system could beadapted for use with other therapeutic equipment for alerting andadvising clinicians regarding detected patient conditions.

This disclosure describes systems and methods for monitoring andevaluating ventilatory parameters, analyzing ventilatory data associatedwith those parameters, and providing useful notifications and/orrecommendations to clinicians. Modern ventilators monitor, evaluate, andgraphically represent a myriad of ventilatory parameters. However, manyclinicians may not easily identify or recognize data patterns andcorrelations indicative of certain patient conditions, changes inpatient condition, and/or effectiveness of ventilatory treatment.Further, clinicians may not readily determine appropriate ventilatoryadjustments that may address certain patient conditions and/or theeffectiveness of ventilatory treatment. Specifically, clinicians may notreadily detect or recognize the presence of asynchrony duringventilation of a patient.

According to embodiments, a ventilator may be configured to monitor andevaluate diverse ventilatory parameters to detect asynchrony and mayissue suitable notifications and recommendations to the clinician whenasynchrony is implicated. The suitable notifications and recommendationsmay further be provided in a hierarchical format such that the clinicianmay selectively access summarized and/or detailed information regardingthe presence of asynchrony. In more automated systems, recommendationsmay be automatically implemented.

Ventilator System

FIG. 1 is a diagram illustrating an embodiment of an exemplaryventilator 100 connected to a human patient 150. Ventilator 100 includesa pneumatic system 102 (also referred to as a pressure generating system102) for circulating breathing gases to and from patient 150 via theventilation tubing system 130, which couples the patient 150 to thepneumatic system 102 via an invasive (e.g., endotracheal tube, as shown)or a non-invasive (e.g., nasal mask) patient interface 180.

Ventilation tubing system 130 (or patient circuit 130) may be a two-limb(shown) or a one-limb circuit for carrying gases to and from the patient150. In a two-limb embodiment, a fitting, typically referred to as a“wye-fitting” 170, may be provided to couple a patient interface 180 (asshown, an endotracheal tube) to an inspiratory limb 132 and anexpiratory limb 134 of the ventilation tubing system 130.

Pneumatic system 102 may be configured in a variety of ways. In thepresent example, pneumatic system 102 includes an expiratory module 108coupled with the expiratory limb 134 and an inspiratory module 104coupled with the inspiratory limb 132. Compressor 106 or other source(s)of pressurized gases (e.g., air, oxygen, and/or helium) is coupled withinspiratory module 104 to provide a gas source for ventilatory supportvia inspiratory limb 132.

The pneumatic system 102 may include a variety of other components,including mixing modules, valves, sensors, tubing, accumulators,filters, etc. Controller 110 is operatively coupled with pneumaticsystem 102, signal measurement and acquisition systems, and an operatorinterface 120 that may enable an operator to interact with theventilator 100 (e.g., change ventilator settings, select operationalmodes, breath types, view monitored parameters, etc.). Controller 110may include memory 112, one or more processors 116, storage 114, and/orother components of the type commonly found in command and controlcomputing devices. In the depicted example, operator interface 120includes a display 122 that may be touch-sensitive and/orvoice-activated, enabling the display 122 to serve both as an input andoutput device.

The memory 112 includes non-transitory, computer-readable storage mediathat stores software that is executed by the processor 116 and whichcontrols the operation of the ventilator 100. In an embodiment, thememory 112 includes one or more solid-state storage devices such asflash memory chips. In an alternative embodiment, the memory 112 may bemass storage connected to the processor 116 through a mass storagecontroller (not shown) and a communications bus (not shown). Althoughthe description of computer-readable media contained herein refers to asolid-state storage, it should be appreciated by those skilled in theart that computer-readable storage media can be any available media thatcan be accessed by the processor 116. That is, computer-readable storagemedia includes non-transitory, volatile and non-volatile, removable andnon-removable media implemented in any method or technology for storageof information such as computer-readable instructions, data structures,program modules or other data. For example, computer-readable storagemedia includes RAM, ROM, EPROM, EEPROM, flash memory or other solidstate memory technology, CD-ROM, DVD, or other optical storage, magneticcassettes, magnetic tape, magnetic disk storage or other magneticstorage devices, or any other medium which can be used to store thedesired information and which can be accessed by the computer.

Communication between components of the ventilatory 100 or between theventilator 100 and other therapeutic equipment and/or remote monitoringsystems may be conducted over a distributed network, as describedfurther herein, via wired or wireless means. Further, the presentmethods may be configured as a presentation layer built over the TCP/IPprotocol. TCP/IP stands for “Transmission Control Protocol/InternetProtocol” and provides a basic communication language for many localnetworks (such as intranets or extranets) and is the primarycommunication language for the Internet. Specifically, TCP/IP is abi-layer protocol that allows for the transmission of data over anetwork. The higher layer, or TCP layer, divides a message into smallerpackets, which are reassembled by a receiving TCP layer into theoriginal message. The lower layer, or IP layer, handles addressing androuting of packets so that they are properly received at a destination.

Ventilator Components

FIG. 2A is a block-diagram illustrating an embodiment of a ventilatorysystem 200 for monitoring and evaluating ventilatory parametersassociated with asynchrony.

Ventilatory system 200 includes ventilator 202 with its various modulesand components. That is, ventilator 202 may further include, inter alia,memory 208, one or more processors 206, user interface 210, andventilation module 212 (which may further include an inspiration module214 and an exhalation module 216). Memory 208 is defined as describedabove for memory 112. Similarly, the one or more processors 206 aredefined as described above for one or more processors 116. Processors206 may further be configured with a clock whereby elapsed time may bemonitored by the ventilatory system 200.

The ventilatory system 200 may also include a display module 204communicatively coupled to ventilator 202. Display module 204 providesvarious input screens, for receiving clinician input, and variousdisplay screens, for presenting useful information to the clinician. Thedisplay module 204 is configured to communicate with user interface 210and may include a graphical user interface (GUI). The GUI may be aninteractive display, e.g., a touch-sensitive screen or otherwise, andmay provide various windows (i.e., visual areas) comprising elements forreceiving user input and interface command operations and for displayingventilatory information (e.g., including ventilatory data, alerts,patient information, parameter settings, etc.). The elements may includecontrols, graphics, charts, tool bars, input fields, smart prompts, etc.Alternatively, other suitable means of communication with the ventilator202 may be provided, for instance by a wheel, keyboard, mouse, or othersuitable interactive device. Thus, user interface 210 may acceptcommands and input through display module 204. Display module 204 mayalso provide useful information in the form of various ventilatory dataregarding the physical condition of a patient and/or a prescribedrespiratory treatment. The useful information may be derived by theventilator 202, based on data collected by a data processing module 222,and the useful information may be displayed to the clinician in the formof graphs, wave representations, pie graphs, or other suitable forms ofgraphic display. For example, one or more smart prompts may be displayedon the GUI and/or display module 204 upon detection of an implication ofasynchrony by the ventilator. Additionally or alternatively, one or moresmart prompts may be communicated to a remote monitoring system coupledvia any suitable means to the ventilatory system 200.

Equation of Motion

Ventilation module 212 may oversee ventilation of a patient according toprescribed ventilatory settings. By way of general overview, the basicelements impacting ventilation may be described by the followingventilatory equation (also known as the Equation of Motion):

P _(m) +P _(v) =V _(T) /C+R*F

Here, P_(m) is a measure of muscular effort that is equivalent to thepressure generated by the muscles of a patient. If the patient's musclesare inactive, the P_(m) is equivalent to 0 cm H₂O. P_(m) is calculatedusing the following equation: P_(m)=elastance×volume+resistance×flow.During inspiration, P_(v) represents the positive pressure delivered bya ventilator (generally in cm H₂O). V_(T) represents the tidal volumedelivered, C refers to the respiratory compliance, R represents therespiratory resistance, and F represents the gas flow during inspiration(generally in liters per min (L/m)). Alternatively, during exhalation,the Equation of Motion may be represented as:

P _(a) +P _(t) =V _(TE) /C+R*F

Here, P_(a) represents the positive pressure existing in the lungs(generally in cm H₂O), P_(t) represents the transairway pressure, V_(TE)represents the tidal volume exhaled, C refers to the respiratorycompliance, R represents the respiratory resistance, and F representsthe gas flow during exhalation (generally in liters per min (L/m)).

Pressure

For positive pressure ventilation, pressure at the upper airway opening(e.g., in the patient's mouth) is positive relative to the pressure atthe body's surface (i.e., relative to the ambient atmospheric pressureto which the patient's body surface is exposed, about 0 cm H₂O). Assuch, when P_(v) is zero, i.e., no ventilatory pressure is beingdelivered, the upper airway opening pressure will be equal to theambient pressure (i.e., about 0 cm H₂O). However, when ventilatorypressure is applied, a pressure gradient is created that allows gases toflow into the airway and ultimately into the lungs of a patient duringinspiration (or, inhalation).

According to embodiments, additional pressure measurements may beobtained and evaluated. For example, transairway pressure, P_(t), whichrefers to the pressure differential or gradient between the upper airwayopening and the alveoli, may also be determined. P_(t) may berepresented mathematically as:

P _(t) =P _(awo) −P _(a)

Where P_(awo) refers to the pressure in the upper airway opening, ormouth, and P_(a) refers to the pressure within the alveolar space, orthe lungs (as described above). P_(t) may also be represented asfollows:

P _(t) =F*R

Where F refers to flow and R refers to respiratory resistance, asdescribed below.

Additionally, lung pressure or alveolar pressure, P_(a), may be measuredor derived. For example, P_(a) may be measured via a distal pressuretransducer or other sensor near the lungs and/or the diaphragm.Alternatively, P_(a) may be estimated by measuring the plateau pressure,P_(Plat), via a proximal pressure transducer or other sensor at or nearthe airway opening. Plateau pressure, P_(Plat), refers to a slightplateau in pressure that is observed at the end of inspiration wheninspiration is held for a period of time, sometimes referred to as aninspiratory hold or pause maneuver, or a breath-hold maneuver. That is,when inspiration is held, pressure inside the alveoli and mouth areequal (i.e., no gas flow). However, as a result of muscular relaxationand elastance of the lungs during the hold period, forces are exerted onthe inflated lungs that create a positive pressure. This positivepressure is observed as a plateau in the pressure waveform that isslightly below the peak inspiratory pressure, P_(Peak), prior toinitiation of exhalation. As may be appreciated, for accuratemeasurement of P_(Plat), the patient should be sedated ornon-spontaneous (as muscular effort during the inspiratory pause mayskew the pressure measurement). Upon determining P_(Plat) based on thepressure waveform or otherwise, P_(Plat) may be used as an estimate ofP_(a) (alveolar pressure).

Flow and Volume

Volume refers to the amount of gas delivered to a patient's lungs,usually in liters (L) or milliliters (ml). Flow refers to a rate ofchange in volume over time (F=ΔV/Δt). Flow is generally expressed inliters per minute (L/m or lpm) or milliliters per minute (mL/m) and,depending on whether gases are flowing into or out of the lungs, flowmay be referred to as inspiratory flow or expiratory flow, respectively.According to embodiments, the ventilator may control the rate ofdelivery of gases to the patient, i.e., inspiratory flow, and maycontrol the rate of release of gases from the patient, i.e., expiratoryflow.

As may be appreciated, volume and flow are closely related. That is,where flow is known or regulated, volume may be derived based on elapsedtime. Indeed, volume may be derived by integrating the flow waveform.According to embodiments, a tidal volume, V_(T), may be delivered uponreaching a set inspiratory time (T_(I)) at set inspiratory flow.Alternatively, set V_(T) and set inspiratory flow may determine theamount of time required for inspiration, i.e., T_(I).

Respiratory Compliance

Additional ventilatory parameters that may be measured and/or derivedmay include respiratory compliance and respiratory resistance, whichrefer to the load against which the patient and/or the ventilator mustwork to deliver gases to the lungs. Respiratory compliance may beinterchangeably referred to herein as compliance. Generally, compliancerefers to a relative ease with which something distends and is theinverse of elastance, which refers to the tendency of something toreturn to its original form after being deformed. As related toventilation, compliance refers to the lung volume achieved for a givenamount of delivered pressure (C=ΔV/ΔP). Increased compliance may bedetected when the ventilator measures an increased volume relative tothe given amount of delivered pressure. Some lung diseases (e.g., acuterespiratory distress syndrome (ARDS)) may decrease compliance and, thus,require increased pressure to inflate the lungs. Alternatively, otherlung diseases may increase compliance, e.g., emphysema, and may requireless pressure to inflate the lungs.

Additionally or alternatively, static compliance and dynamic compliancemay be calculated. Static compliance, C_(s), represents complianceimpacted by elastic recoil at zero flow (e.g., of the chest wall,patient circuit, and alveoli). As elastic recoil of the chest wall andpatient circuit may remain relatively constant, static compliance maygenerally represent compliance as affected by elastic recoil of thealveoli. As described above, P_(Plat) refers to a slight plateau inpressure that is observed after relaxation of pleural muscles andelastic recoil, i.e., representing pressure delivered to overcomeelastic forces. As such, P_(Plat) provides a basis for estimating C_(s)as follows:

C _(S) =V _(T)/(P _(Plat)−EEP)

Where V_(T) refers to tidal volume, P_(Plat) refers to plateau pressure,and EEP refers to end-expiratory pressure, or baseline pressure(including PEEP and/or Auto-PEEP). Note that proper calculation of C_(S)depends on accurate measurement of V_(T) and P_(Plat).

Dynamic compliance, C_(D), is measured during airflow and, as such, isimpacted by both elastic recoil and airway resistance. Peak inspiratorypressure, P_(Peak), which represents the highest pressure measuredduring inspiration, i.e., pressure delivered to overcome both elasticand resistive forces to inflate the lungs, is used to calculate C_(D) asfollows:

C _(D) =V _(T)/(P _(Peak)−EEP)

Where V_(T) refers to tidal volume, P_(Peak) refers to peak inspiratorypressure, and EEP refers to end-expiratory pressure. According toembodiments, ventilatory data may be more readily available for trendingcompliance of non-triggering patients than of triggering patients.

Respiratory Resistance

Respiratory resistance refers to frictional forces that resist airflow,e.g., due to synthetic structures (e.g., endotracheal tube, expiratoryvalve, etc.), anatomical structures (e.g., bronchial tree, esophagus,etc.), or viscous tissues of the lungs and adjacent organs. Respiratoryresistance may be interchangeably referred to herein as resistance.Resistance is highly dependent on the diameter of the airway. That is, alarger airway diameter entails less resistance and a higher concomitantflow. Alternatively, a smaller airway diameter entails higher resistanceand a lower concomitant flow. In fact, decreasing the diameter of theairway results in an exponential increase in resistance (e.g., two-timesreduction of diameter increases resistance by sixteen times). As may beappreciated, resistance may also increase due to a restriction of theairway that is the result of, inter alia, increased secretions,bronchial edema, mucous plugs, bronchospasm, and/or kinking of thepatient interface (e.g., invasive endotracheal or tracheostomy tubes).

Airway resistance may further be represented mathematically as:

R=P _(t) /F

Where P_(t) refers to the transairway pressure and F refers to the flow.That is, P_(t) refers to the pressure necessary to overcome resistiveforces of the airway. Resistance may be expressed in centimeters ofwater per liter per second (i.e., cm H₂O/L/s).

Pulmonary Time Constant

As discussed above, compliance refers to the lung volume achieved for agiven amount of delivered pressure (C=ΔV/ΔP). That is, stateddifferently, volume delivered is equivalent to the compliance multipliedby the delivered pressure (ΔV=C*ΔP). However, as the lungs are notperfectly elastic, a period of time is needed to deliver the volume ΔVat pressure ΔP. A pulmonary time constant, τ, may represent a timenecessary to inflate or exhale a given percentage of the volume atdelivered pressure ΔP. The pulmonary time constant, τ, may be calculatedby multiplying the respiratory resistance by the respiratory compliance(τ=R*C) for a given patient and τ is generally represented in seconds,s. The pulmonary time constant associated with exhalation of the givenpercentage of volume may be termed an expiratory time constant and thepulmonary time constant associated with inhalation of the givenpercentage of volume may be termed an inspiratory time constant.

According to some embodiments, when expiratory resistance data isavailable, the pulmonary time constant may be calculated by multiplyingexpiratory resistance by compliance. According to alternativeembodiments, the pulmonary time constant may be calculated based oninspiratory resistance and compliance. According to further embodiments,the expiratory time, T_(E), should be equal to or greater than three (3)pulmonary time constants to ensure adequate exhalation. That is, for atriggering patient, T_(E) (e.g., determined by trending T_(E) orotherwise) should be equal to or greater than 3 pulmonary timeconstants. For a non-triggering patient, set respiration rate (RR)should yield a T_(E) that is equal to or greater than 3 pulmonary timeconstants.

Normal Resistance and Compliance

According to embodiments, normal respiratory resistance and compliancemay be determined based on a patient's predicted body weight (PBW) (orideal body weight (IBW)). That is, according to a standardized protocolor otherwise, patient data may be compiled such that normal respiratoryresistance and compliance values and/or ranges of values may bedetermined and provided to the ventilatory system 200. That is, amanufacturer, clinical facility, clinician, or otherwise, may configurethe ventilator with normal respiratory resistance and compliance valuesand/or ranges of values based on PBWs (or IBWs) of a patient population.Thereafter, during ventilation of a particular patient, respiratoryresistance and compliance data may be trended for the patient andcompared to normal values and/or ranges of values based on theparticular patient's PBW (or IBW). According to embodiments, theventilator may give an indication to the clinician regarding whether thetrended respiratory resistance and compliance data of the particularpatient falls into normal ranges. According to some embodiments, datamay be more readily available for trending resistance and compliance fornon-triggering patients than for triggering patients.

According to further embodiments, a predicted T_(E) may be determinedbased on a patient's PBW (or IBW). That is, according to a standardizedprotocol or otherwise, patient population data may be compiled such thatpredicted T_(E) values and/or ranges of values may be determined basedon PBWs (or IBWs) of the patient population and provided to theventilatory system 200. Actual (or trended) T_(E) for a particularpatient may then be compared to the predicted T_(E). As notedpreviously, increased resistance and/or compliance may result in anactual T_(E) that is longer than predicted T_(E). However, when actualT_(E) is consistent with predicted T_(E), this may indicate thatresistance and compliance for the particular patient fall into normalranges.

According to further embodiments, a normal pulmonary time constant, τ,may be determined based on a patient's PBW (or IBW). That is, accordingto a standardized protocol or otherwise, patient data may be compiledsuch that normal τ values and/or ranges of values may be determinedbased on PBWs (or IBWs) of a patient population and provided to theventilatory system 200. A calculated τ may be determined for aparticular patient by multiplying resistance by compliance (as describedabove, resistance and compliance data may be more readily available fora non-triggering patient). As the product of resistance and complianceresults in τ, increased resistance and/or compliance may result in anelevated τ value. However, when the calculated τ value for theparticular patient is consistent with the normal τ value, this mayindicate that the resistance and compliance of the particular patientfall into normal ranges.

Inspiration

Ventilation module 212 may further include an inspiration module 214configured to deliver gases to the patient according to prescribedventilatory settings. Specifically, inspiration module 214 maycorrespond to the inspiratory module 104 or may be otherwise coupled tosource(s) of pressurized gases (e.g., air, oxygen, and/or helium), andmay deliver gases to the patient. Inspiration module 214 may beconfigured to provide ventilation according to various ventilatorybreath types, e.g., via volume-targeted, pressure-targeted, or via anyother suitable breath types.

The various ventilator breath types operate in different modes such asmandatory, mixed, and spontaneous modes. In some embodiments, the modeof operation is selected by the clinician. In other embodiments, themode of operation is automatically determined by the ventilator. Duringthe spontaneous mode of operation, a breath type delivers inspirationand exhalation upon the detection of inspiratory and/or expiratoryeffort by the patient according to the parameters of the breath type.However, for safety measures, a breath type in a spontaneous mode maydeliver inspiration and expiration after a predetermined amount of timepasses to insure that the patient receives breathing gas in the eventthe patient stops making inspiratory and/or expiratory patient efforts.During the mandatory mode of operation, a breath type deliversinspiration and exhalation according to parameters of the breath typeregardless of patient inspiratory and expiratory efforts. During themixed mode of operation, a breath type delivers inspiration andexpiration to the patient according to the parameters of the breathtype; however, if a patient inspiratory and/or expiratory effort isdetected by the breath type during an mixed mode, the breath type willdeliver an additional inspiration and/or expiration upon detectionaccording to parameters of the breath type regardless of the nextdetermined timing for delivery of inspiration and/or expiration by thebreath type.

Volume ventilation refers to various forms of volume-targetedventilation that regulate volume delivery to the patient. Differenttypes of volume ventilation are available depending on the specificimplementation of volume regulation. For example, for volume-cycledventilation, an end of inspiration is determined based on monitoring thevolume delivered to the patient. Volume ventilation may includevolume-control (VC), volume-targeted-pressure-control (VC+), orvolume-support (VS) breath types. Volume ventilation may be accomplishedby setting a target volume, or prescribed tidal volume, V_(T), fordelivery to the patient. According to embodiments, prescribed V_(T) andinspiratory time (T_(I)) may be set during ventilation start-up, basedon the patient's PBW (or IBW). In this case, flow will be dependent onthe prescribed V_(T) and set T_(I). Alternatively, prescribed V_(T) andflow may be set and T_(I) may result. According to some embodiments, apredicted T_(E) may be determined based on normal respiratory andcompliance values or value ranges based on the patient's PBW (or IBW).Additionally, a RR setting, generally in breaths/min, may be determinedand configured. For a non-triggering patient, the set RR controls thetiming for each inspiration. For a triggering patient, the RR settingapplies if the patient stops triggering for some reason and/or thepatient's triggered RR drops below a threshold level.

According to embodiments, during volume ventilation, as volume and floware regulated by the ventilator, delivered V_(T), flow waveforms (orflow traces), and volume waveforms may be constant and may not beaffected by variations in lung or airway characteristics (e.g.,respiratory compliance and/or respiratory resistance). Alternatively,pressure readings may fluctuate based on lung or airway characteristics.According to some embodiments, the ventilator may control theinspiratory flow and then derive volume based on the inspiratory flowand elapsed time. For volume-cycled ventilation, when the derived volumeis equal to the prescribed V_(T), the ventilator may initiateexhalation.

According to alternative embodiments, the inspiration module 214 mayprovide ventilation via a form of pressure ventilation.Pressure-targeted breath types may be provided by regulating thepressure delivered to the patient in various ways. For example, duringpressure-cycled ventilation, an end of inspiration is determined basedon monitoring the pressure delivered to the patient. Pressureventilation may include a pressure-support (PS), a proportional assist(PA), tube compensation (TC), or a pressure-control (PC) breath type,for example. The proportional assist (PA) breath type provides pressurein proportion to the instantaneous patient effort during spontaneousventilation and is based on the equation of motion. Pressure ventilationmay also include various forms of bi-level (BL) pressure ventilation,i.e., pressure ventilation in which the inspiratory positive airwaypressure (IPAP) is higher than the expiratory positive airway pressure(EPAP). Specifically, pressure ventilation may be accomplished bysetting a target or prescribed pressure for delivery to the patient.During pressure ventilation, predicted T_(I) may be determined based onnormal respiratory and compliance values and on the patient's PBW (orIBW). According to some embodiments, a predicted T_(E) may be determinedbased on normal respiratory and compliance values and based on thepatient's PBW (or IBW). A respiratory rate (RR) setting may also bedetermined and configured. For a non-triggering patient, the set RRcontrols the timing for each inspiration. For a triggering patient, theRR setting applies if the patient stops triggering for some reasonand/or patient triggering drops below a threshold RR level.

According to embodiments, during pressure ventilation, the ventilatormay maintain the same pressure waveform at the mouth, P_(awo),regardless of variations in lung or airway characteristics, e.g.,respiratory compliance and/or respiratory resistance. However, thevolume and flow waveforms may fluctuate based on lung and airwaycharacteristics. As noted above, pressure delivered to the upper airwaycreates a pressure gradient that enables gases to flow into a patient'slungs. The pressure from which a ventilator initiates inspiration istermed the end-expiratory pressure (EEP) or “baseline” pressure. Thispressure may be atmospheric pressure (about 0 cm H₂O), also referred toas zero end-expiratory pressure (ZEEP). However, commonly, the baselinepressure may be positive, termed positive end-expiratory pressure(PEEP). Among other things, PEEP may promote higher oxygenationsaturation and/or may prevent alveolar collapse during exhalation. Underpressure-cycled ventilation, upon delivering the prescribed pressure theventilator may initiate exhalation.

According to still other embodiments, a combination of volume andpressure ventilation may be delivered to a patient, e.g.,volume-targeted-pressure-control (VC+) breath type. In particular, VC+may provide benefits of setting a target V_(T), while also allowing formonitoring variations in flow. In other embodiments, a positive feedbackventilation is delivered to the patient, e.g., a diaphragmaticelectromyography adjusted (DEA) breath type, or an IE Sync breath type(IE Sync is a registered trademark of Nellcor Puritan Bennett, LLClocated at 6135 Gunbarrel Avenue in Boulder, Colo. 80301). As will bedetailed further below, variations in flow may be indicative of variouspatient conditions. The use of an IE Synch or DEA breath type providesfor more sensitive trigger detection for spontaneously breathingpatients compared to other utilized breath types.

Exhalation

Ventilation module 212 may further include an exhalation module 216configured to release gases from the patient's lungs according toprescribed ventilatory settings. Specifically, exhalation module 216 maycorrespond to expiratory module 108 or may otherwise be associated withand/or controlling an expiratory valve for releasing gases from thepatient. By way of general overview, a ventilator may initiateexhalation based on lapse of an inspiratory time setting (T_(I)) orother cycling criteria set by the clinician or derived from ventilatorsettings (e.g., detecting delivery of prescribed V_(T) or prescribedpressure based on a reference trajectory). Upon initiating theexpiratory phase, exhalation module 216 may allow the patient to exhaleby opening an expiratory valve. As such, exhalation is passive, and thedirection of airflow, as described above, is governed by the pressuregradient between the patient's lungs (higher pressure) and the ambientsurface pressure (lower pressure). Although expiratory flow is passive,it may be regulated by the ventilator based on the size of theexpiratory valve opening. In some embodiments, exhalation is regulatedbased on a selected breath type.

Expiratory time (T_(E)) is the time from the end of inspiration untilthe patient triggers for a spontaneously breathing patient. The cycledetection for exhalation may be based on a selected trigger type. For anon-triggering patient, the T_(E) is the time from the end ofinspiration until the next inspiration based on the set RR. In somecases, however, the time required to return to the functional residualcapacity (FRC) or resting capacity of the lungs is longer than providedby T_(E) (e.g., because the patient triggers prior to fully exhaling orthe set RR is too high for a non-triggering patient). According toembodiments, various ventilatory settings may be adjusted to bettermatch the time to reach FRC with the time available to reach FRC. Forexample, increasing flow will shorten T_(I), thereby increasing theamount of time available to reach FRC. Alternatively, V_(T) may bedecreased, resulting in less time required to reach FRC.

As may be further appreciated, at the point of transition betweeninspiration and exhalation, the direction of airflow may abruptly changefrom flowing into the lungs to flowing out of the lungs or vice versadepending on the transition. Stated another way, inspiratory flow may bemeasurable in the ventilatory circuit until P_(Peak) is reached, atwhich point flow is zero. Thereafter, upon initiation of exhalation,expiratory flow is measurable in the ventilatory circuit until thepressure gradient between the lungs and the body's surface reaches zero(again, resulting in zero flow). However, in some cases, as will bedescribed further herein, expiratory flow may still be positive, i.e.,measurable, at the end of exhalation (termed positive end-expiratoryflow or positive EEF). In this case, positive EEF is an indication thatthe pressure gradient has not reached zero or, similarly, that thepatient has not completely exhaled. Although a single occurrence ofpremature inspiration may not warrant concern, repeated detection ofpositive EEF may be indicative of Auto-PEEP.

Ventilator Synchrony and Patient Triggering

According to some embodiments, the inspiration module 214 and/or theexhalation module 216 may be configured to synchronize ventilation witha spontaneously-breathing, or triggering, patient. That is, theventilator may be configured to detect patient effort and may initiate atransition from exhalation to inspiration (or from inspiration toexhalation) in response. Triggering refers to the transition fromexhalation to inspiration in order to distinguish it from the transitionfrom inspiration to exhalation (referred to as cycling). Ventilationsystems, depending on their breath type, may trigger and/or cycleautomatically, or in response to a detection of patient effort, or both.

In the medical device field, “patient effort” is a term that can be usedto describe many different patient parameters. To be clear, for thepurposes of this document, the term “patient effort” shall be usedherein to mean a patient's spontaneous attempt to initiate aninspiration or an exhalation as determined by an analysis of pressure,flow, volume, etc. measured by the ventilator. For example, a drop inpressure of greater than a threshold amount may be detected andidentified as a single effort of the patient to initiate an inspiration.At times, the phrase “patient inspiratory effort” or “patient expiratoryeffort” will be used instead of patient effort to remind the reader thatwhat is meant is an attempt by the patient to change the phase ofrespiratory cycle.

There are several different trigger types or systems and/methodsutilized by the ventilator for detecting patient triggers and/or cycles.Once a breath type is selected, the trigger type utilized by the breathtype for detecting patient effort may be selected. In some embodiments,the trigger type utilized by the breath type is automatically selectedby the ventilator. In other embodiments, the trigger type utilized bythe breath type is selected by the operator.

Any suitable type of triggering detection for determining a patienttrigger may be utilized by the ventilator, such as nasal detection,diaphragm detection, and/or brain signal detection. Further, theventilator may detect patient triggering via a pressure-monitoringmethod, a flow-monitoring method, direct or indirect measurement ofneuromuscular signals, or any other suitable method. Internal sensors220 and/or distributed sensors 218 suitable for this detection mayinclude any suitable sensing device as known by a person of skill in theart for a ventilator. In addition, the sensitivity of the ventilator tochanges in pressure and/or flow may be adjusted such that the ventilatormay properly detect the patient effort, i.e., the lower the pressure orflow change setting the more sensitive the ventilator may be to patienttriggering.

According to embodiments, a pressure-triggering method may involve theventilator monitoring the circuit pressure, as described above, anddetecting a slight drop in circuit pressure. The slight drop in circuitpressure may indicate that the patient's respiratory muscles, P_(m), arecreating a slight negative pressure gradient between the patient's lungsand the airway opening in an effort to inspire. The ventilator mayinterpret the slight drop in circuit pressure as patient effort and mayconsequently initiate inspiration by delivering respiratory gases.

Alternatively, the ventilator may detect a flow-triggered event.Specifically, the ventilator may monitor the circuit flow, as describedabove. If the ventilator detects a slight drop in flow duringexhalation, this may indicate, again, that the patient is attempting toinspire. In this case, the ventilator is detecting a drop in bias flow(or baseline flow) attributable to a slight redirection of gases intothe patient's lungs (in response to a slightly negative pressuregradient as discussed above). Bias flow refers to a constant flowexisting in the circuit during exhalation that enables the ventilator todetect expiratory flow changes and patient triggering. For example,while gases are generally flowing out of the patient's lungs duringexhalation, a drop in flow may occur as some gas is redirected and flowsinto the lungs in response to the slightly negative pressure gradientbetween the patient's lungs and the body's surface. Thus, when theventilator detects a slight drop in flow below the bias flow by apredetermined threshold amount (e.g., 2 L/min below bias flow), it mayinterpret the drop as a patient trigger and may consequently initiateinspiration by delivering respiratory gases.

Further, in some embodiments, the trigger type may be an “active triggertype” or a “background trigger type”. The active trigger type determineswhen to deliver inspiration and/or expiration to the patient duringventilation by the ventilator and the ventilator actively deliversinspiration and/or expiration based on this determination. A backgroundtrigger type determines when to deliver inspiration and/or expiration tothe patient during ventilation by the ventilator but the ventilator doesnot actively deliver inspiration and/or expiration based on thisdetermination and is, therefore, merely running in the background. Anytrigger type described herein may be an active trigger type or abackground trigger type.

Volume-Control Breath Type

In some embodiments, ventilation module 212 may further include aninspiration module 214 configured to deliver gases to the patientaccording to volume-control (VC). The VC breath type allows a clinicianto set a respiratory rate and to select a volume to be administered to apatient during a mandatory breath. When using VC, a clinician sets adesired tidal volume, flow wave form shape, and an inspiratory flow rateor inspiratory time. These variables determine how much volume of gas isdelivered to the patient and the duration of inspiration during eachmandatory breath inspiratory phase. The mandatory breaths areadministered according to the set respiratory rate.

For VC, when the delivered volume is equal to the prescribed tidalvolume, the ventilator may initiate exhalation. Exhalation lasts fromthe time at which prescribed volume is reached until the start of thenext ventilator mandated inspiration. This exhalation time is determinedby the respiratory rate set by the clinician and any participation abovethe set rate by the patient. Upon the end of exhalation, another VCmandatory breath is given to the patient.

During VC, delivered volume and flow waveforms may remain constant andmay not be affected by variations in lung or airway characteristics.Alternatively, pressure readings may fluctuate based on lung or airwaycharacteristics. According to some embodiments, the ventilator maycontrol the inspiratory flow and then derive volume based on theinspiratory flow and elapsed time.

In some embodiments, VC may also be delivered to a triggering patient.When VC is delivered to a triggering patient, the breath period (i.e.time between breaths) is a function of the frequency at which thepatient is triggering breaths. That is, the ventilator will trigger theinhalation based upon the respiratory rate setting or the patienteffort. If no patient effort is detected, the ventilator will deliveranother mandatory breath at the predetermined respiratory rate. Apatient-initiated mandatory (PIM) breath is a control breath that istriggered by the patient during a control mode such as VC or PC.

Volume-Targeted-Pressure-Control Breath Type

In further embodiments, ventilation module 212 may further include aninspiration module 214 configured to deliver gases to the patient usinga volume-targeted-pressure-control (VC+) breath type. The VC+ breathtype is a combination of volume and pressure control breath types thatmay be delivered to a patient as a mandatory breath. In particular, VC+may provide the benefits associated with setting a target tidal volume,while also allowing for variable flow. Variable flow may be helpful inmeeting inspiratory flow demands for actively breathing patients.

As may be appreciated, when resistance increases it becomes moredifficult to pass gases into and out of the lungs, decreasing flow. Forexample, when a patient is intubated, i.e., having either anendotracheal or a tracheostomy tube in place, resistance may beincreased as a result of the smaller diameter of the tube over apatient's natural airway. In addition, increased resistance may beobserved in patients with obstructive disorders, such as COPD, asthma,etc. Higher resistance may necessitate, inter alia, a higher inspiratorytime setting for delivering a prescribed pressure or volume of gases, alower respiratory rate resulting in a higher expiratory time forcomplete exhalation of gases.

Unlike VC, when the set inspiratory time is reached, the ventilator mayinitiate exhalation. Exhalation lasts from the end of inspiration untilthe beginning of the next inspiration. For a non-triggering patient, theexpiratory time (T_(E)) is based on the respiratory rate set by theclinician. Upon the end of exhalation, another VC+ mandatory breath isgiven to the patient.

By controlling target tidal volume and allowing for variable flow, VC+allows a clinician to maintain the volume while allowing the flow andpressure targets to fluctuate.

Volume-Support Breath Type

In some embodiments, ventilation module 212 may further include aninspiration module 214 configured to deliver gases to the patientaccording to volume-support (VS) breath type. The VS breath type isutilized in the present disclosure as a spontaneous breath. VS isgenerally used with a triggering (spontaneously breathing) patient whenthe patient is ready to be weaned from a ventilator or when the patientcannot do all of the work of breathing on his or her own. When theventilator senses patient inspiratory effort, the ventilator delivers aset tidal volume during inspiration. The tidal volume may be set andadjusted by the clinician. The patient controls the rate, inspiratoryflow, and has some control over the inspiratory time. The ventilatorthen adjusts the pressure over several breaths to achieve the set tidalvolume. When the machine senses a decrease in flow, or inspiration timereaches a predetermined limit, the ventilator determines thatinspiration is ending. When delivered as a spontaneous breath,exhalation in VS lasts from a determination that inspiration is endinguntil the ventilator senses a next patient effort to breath.

Pressure-Control Breath Type

In additional embodiments, ventilation module 212 may further include aninspiration module 214 configured to deliver gases to the patientaccording to the pressure-control (PC) breath type. PC allows aclinician to select a pressure to be administered to a patient during amandatory breath. When using the PC breath type, a clinician sets adesired pressure, inspiratory time, and respiratory rate for a patient.These variables determine the pressure of the gas delivered to thepatient during each mandatory breath inspiration. The mandatory breathsare administered according to the set respiratory rate.

For the PC breath type, when the inspiratory time is equal to theprescribed inspiratory time, the ventilator may initiate exhalation.Exhalation lasts from the end of inspiration until the next inspiration.Upon the end of exhalation, another PC mandatory breath is given to thepatient.

During PC breaths, the ventilator may maintain the same pressurewaveform at the mouth, regardless of variations in lung or airwaycharacteristics, e.g., respiratory compliance and/or respiratoryresistance. However, the volume and flow waveforms may fluctuate basedon lung and airway characteristics.

In some embodiments, PC may also be delivered for triggering patients.When PC is delivered with triggering, the breath period (i.e. timebetween breaths) is a function of the respiratory rate of the patient.The ventilator will trigger the inhalation based upon the respiratoryrate setting or the patient's trigger effort, but cycling to exhalationwill be based upon elapsed inspiratory time. The inspiratory time is setby the clinician. The inspiratory flow is delivered based upon thepressure setting and patient physiology. Should the patient create anexpiratory effort in the middle of the mandatory inspiratory phase, theventilator will respond by reducing flow. If no patient effort isdetected, the ventilator will deliver another mandatory breath at thepredetermined respiratory rate.

PC with triggering overcomes some of the problems encountered by othermandatory breath types that use artificially set inspiratory flow rates.For example, if the inspiratory flow is artificially set lower than apatient's demand, the patient will feel starved for flow. This can leadto undesirable effects, including increased work of breathing. Inaddition, should the patient begin to exhale when using one of thetraditional mandatory breath types, the patient's expiratory effort isignored since the inspiratory flow is mandated by the ventilatorsettings.

Pressure-Support Breath Type

In further embodiments, ventilation module 212 may further include aninspiration module 214 configured to deliver gases to the patientaccording to a pressure-support (PS) breath type. PS is a form ofassisted ventilation and is utilized in the present disclosure during aspontaneous breath. PS is a patient triggered breath and is typicallyused when a patient is ready to be weaned from a ventilator or for whenpatients are breathing spontaneously but cannot do all the work ofbreathing on their own. When the ventilator senses patient inspiratoryeffort, the ventilator provides a constant pressure during inspiration.The pressure may be set and adjusted by the clinician. The patientcontrols the rate, inspiratory flow, and to an extent, the inspiratorytime. The ventilator delivers the set pressure and allows the flow tovary. When the machine senses a decrease in flow, or determines thatinspiratory time has reached a predetermined limit, the ventilatordetermines that inspiration is ending. When delivered as a spontaneousbreath, exhalation in PS lasts from a determination that inspiration isending until the ventilator senses a patient effort to breath.

Proportional Assist Breath Type

In mechanical ventilation, a proportional assist (PA) breath type refersto a type of ventilation in which the ventilator acts as an inspiratoryamplifier that provides pressure support based on the patient's work ofbreathing (WOB). The degree of amplification (the “support setting”) isset by an operator, for example, as a percentage based on the patient'sWOB. In one implementation of a PA breath type, the ventilator maycontinuously monitor the patient's instantaneous inspiratory flow andinstantaneous net lung volume, which are indicators of the patient'sinspiratory WOB. These signals, together with ongoing estimates of thepatient's lung compliance and lung resistance, allow the ventilator tocompute a patient WOB and derive therefrom a target pressure to providethe support that assists the patient's inspiratory muscles to the degreeselected by the operator as the support setting.

Various methods are known for calculation of patient WOB and anysuitable method may be used. For example, methods exist that calculatepatient WOB from sensors attached to the body to detect neural ormuscular activity as well as methods that determine a patient WOB basedon respiratory flow, respiratory pressure or a combination of both flowand pressure.

In a PA breath type, the patient's work of breathing, the elastic workof breathing component, and/or the resistive WOB component may beestimated by inputting measurements from various internal sensors 220and/or distributed sensors 218 into the breathing algorithms. Typically,none of the instantaneous inspiratory pressure, the instantaneous flow,or the resulting volume are set by the caregiver. Because the PA breathtype harmoniously links the ventilator to the patient, the patienteffectively “drives” the ventilator. By appropriately setting the valueof the proportionality (% support or support setting) control, thecaregiver may effectively partition the total work of breathing betweenthe patient and the ventilator.

Tube Compensation Breath Type

A Tube Compensation (TC) breath type is similar to the PA breath type.The TC breath type delivers breathing gases to a spontaneously-breathingpatient with the objective of reducing the patient's work of breathingimposed by an artificial airway. During a TC breath type, the ventilatorcompensates for the load associated with breathing through anendotracheal or tracheostomy tube. The TC breath type calculates a tuberesistance based on the tube type (endotracheal or tracheostomy) and thetube's internal diameter (tube_(I.D.)), which are settings input by theclinician. A tube compensation pressure is then calculated by theventilator during the TC breath type as a function of the patient'smonitored flow, the calculated tube resistance, and a percent supportsetting (also known as support setting) input by the clinician. Duringinhalation, the ventilator during the TC breath type delivers the tubecompensation pressure plus a set PEEP to the patient airway. Uponreaching an expiration sensitivity (E_(SENS)) setting (or other cyclingcriteria), the ventilator during the TC breath type initiatesexhalation. As with other pressure-based breath types, the ventilatorduring the TC breath type does not target a set V_(T) or flow pattern.

Expiratory Sensitivity

As discussed above, ventilation module 212 may oversee ventilation of apatient according to prescribed ventilatory settings. In one embodiment,the expiratory sensitivity (E_(SENS)) is set by a clinician or operator.According to embodiments, E_(SENS) sets the percentage of delivered peakinspiratory flow necessary to terminate inspiration and initiateexhalation. In some embodiments, the clinician or operator determinesthe E_(SENS) setting, which is adjustable from 1% to 80%. A lower setE_(SENS) increases inspiration time and a higher set E_(SENS) decreasesinspiration time. The E_(SENS) setting may be utilized to limitunnecessary expiratory work and to improve patient-ventilator synchrony.

IE Sync Breath Type

The IE Sync breath delivers inspiration and expiration duringventilation of a spontaneously breathing patient based on monitored orestimated intrapleural pressure. The term “intrapleural pressure,” asused herein, refers generally to the pressure exerted by the patient'sdiaphragm on the cavity in the thorax that contains the lungs, or thepleural cavity, and should further represent estimates of the pressureand/or any derivatives thereof. The use of intrapleural pressure is aneffective way to determine inspiratory and expiratory patient effort.When a patient makes an effort to breathe, the patient's diaphragm willcontract, and decrease the intrapleural pressure in order to draw air(or another substance) into the lungs. Because the contraction of thediaphragm is the effect of patient effort, the intrapleural pressurechange is the first and a direct way to determine patient effort, as apressure/flow change will happen subsequently. Therefore, a triggerdetection application that uses intrapleural pressure is more sensitiveto patient efforts than a trigger detection application that only usespressure or flow. Accordingly, the IE Sync breath type promotespatient-ventilator synchrony. The improved synchrony provided by the IESync breath type minimizes patient discomfort.

The triggering described above based on intrapleural pressure asutilized by the IE Sync breath type is an additional trigger type.Accordingly, this IE Sync trigger type (or intrapleural pressure triggertype) may be an active trigger type (i.e., when utilized during the IESync breath type to deliver ventilation) or a background trigger type(when utilized in background).

Intrapleural pressure is estimated by the IE Sync algorithm according toany suitable method either known or discovered in the future. Theintrapleural pressure estimates and their associated values can beutilized to monitor ventilation in all modes. In some embodiments, theIE Sync breath type derives intrapleural pressure readings from otherdata and measurements according to mathematical operations or otherwise.For example, an algorithm that estimates how the patient's intrapleuralpressure is changing in real-time or quasi-real based on measuredpressure and flow may be used. In one embodiment, an algorithm utilizesmeasured pressure, inlet flow, and outlet flow to determine intrapleuralpressure. In some embodiments, the measured pressure and flow arederived from data taken by internal sensors 220 and distributed sensors218. An example algorithm for determining intrapleural pressure isdescribed in U.S. patent application Ser. No. 12/980,583 filed Dec. 29,2010. Accordingly, U.S. patent application Ser. No. 12/980,583 filed onDec. 29, 2010, is incorporated herein by reference in its entirety.

Diaphragmatic Electromyography Adjust Breath Type

The DEA breath delivers inspiration and expiration during ventilation ofa spontaneously breathing patient based on monitored neural respiratoryoutput for the diaphragm, which is monitored with an electromyograph.The neural respiratory output, which the act of breathing depends on, isthe result of a rhythmic discharge from the center of brain. Thedischarge is carried to the diaphragm muscles cells via the phrenicnerve causing the diaphragm muscles to contract. The contraction ofdiaphragm muscles causes the lungs to expand dropping pressure in theairways of lungs to provide an inflow of air into the lungs.

The neural output is the captured electrical activity of the diaphragm(Edi). The Edi is then fed to the ventilator and used by the ventilatorto assist the patient's breathing. The Edi curve and its associatedvalues can be utilized to monitor ventilation in all modes. For example,the Edi curve and its associated values may be utilized to determinerespiratory drive, volume requirements, effect of a ventilation setting,and gain indications for sedation and weaning.

Because the ventilator and the diaphragm are triggered utilizing thesame signal, the mechanical coupling between the ventilator and thediaphragm is almost instantaneous. The Edi signal may be utilized totrigger inspiration and expiration; therefore, the DEA breath typepromotes patient-ventilator synchrony. Further, with the DEA breath typethe patient's own respiratory demand is utilized to determine the levelof assistance helping to provide the correct breathing assistance to thepatient. Accordingly, the improved synchrony provided by the DEA breathtype minimizes patient discomfort.

The triggering described above based on Edi and utilized by the DEAbreath type is an additional trigger type. Accordingly, this DEA triggertype (or Edi trigger type) may be an active trigger type (i.e., whenutilized during the DEA breath type to deliver ventilation) or abackground trigger type (when utilized in the background).

Ventilator Sensory Devices

The ventilatory system 200 may also include one or more distributedsensors 218 communicatively coupled to ventilator 202. Distributedsensors 218 may communicate with various components of ventilator 202,e.g., ventilation module 212, internal sensors 220, data processingmodule 222, asynchrony detection module 224, and any other suitablecomponents and/or modules. Distributed sensors 218 may detect changes inventilatory parameters indicative of asynchrony, for example.Distributed sensors 218 may be placed in any suitable location, e.g.,within the ventilatory circuitry or other devices communicativelycoupled to the ventilator. For example, sensors may be affixed to theventilatory tubing or may be imbedded in the tubing itself. According tosome embodiments, sensors may be provided at or near the lungs (ordiaphragm) for detecting a pressure in the lungs. Additionally oralternatively, sensors may be affixed or imbedded in or near wye-fitting170 and/or patient interface 180, as described above.

Distributed sensors 218 may further include pressure transducers thatmay detect changes in circuit pressure (e.g., electromechanicaltransducers including piezoelectric, variable capacitance, or straingauge). Distributed sensors 218 may further include various flowmetersfor detecting airflow (e.g., differential pressure pneumotachometers).For example, some flowmeters may use obstructions to create a pressuredecrease corresponding to the flow across the device (e.g., differentialpressure pneumotachometers) and other flowmeters may use turbines suchthat flow may be determined based on the rate of turbine rotation (e.g.,turbine flowmeters). Alternatively, sensors may utilize optical orultrasound techniques for measuring changes in ventilatory parameters. Apatient's blood parameters or concentrations of expired gases may alsobe monitored by sensors to detect physiological changes that may be usedas indicators to study physiological effects of ventilation, wherein theresults of such studies may be used for diagnostic or therapeuticpurposes. Indeed, any distributed sensory device useful for monitoringchanges in measurable parameters during ventilatory treatment may beemployed in accordance with embodiments described herein.

Ventilator 202 may further include one or more internal sensors 220.Similar to distributed sensors 218, internal sensors 220 may communicatewith various components of ventilator 202, e.g., ventilation module 212,internal sensors 220, data processing module 222, asynchrony detectionmodule 224, and any other suitable components and/or modules. Internalsensors 220 may employ any suitable sensory or derivative technique formonitoring one or more parameters associated with the ventilation of apatient. However, the one or more internal sensors 220 may be placed inany suitable internal location, such as, within the ventilatorycircuitry or within components or modules of ventilator 202. Forexample, sensors may be coupled to the inspiratory and/or expiratorymodules for detecting changes in, for example, circuit pressure and/orflow. Specifically, internal sensors 220 may include pressuretransducers and flowmeters for measuring changes in circuit pressure andairflow. Additionally or alternatively, internal sensors 220 may utilizeoptical or ultrasound techniques for measuring changes in ventilatoryparameters. For example, a patient's expired gases may be monitored byinternal sensors 220 to detect physiological changes indicative of thepatient's condition and/or treatment, for example. Indeed, internalsensors 220 may employ any suitable mechanism for monitoring parametersof interest in accordance with embodiments described herein.

As should be appreciated, with reference to the Equation of Motion,ventilatory parameters are highly interrelated and, according toembodiments, may be either directly or indirectly monitored. That is,parameters may be directly monitored by one or more sensors, asdescribed above, or may be indirectly monitored by derivation accordingto the Equation of Motion.

Ventilatory Data

Ventilator 202 may further include a data processing module 222. Asnoted above, distributed sensors 218 and internal sensors 220 maycollect data regarding various ventilatory parameters. Ventilator datarefers to any ventilatory parameter or setting. A ventilatory parameterrefers to any factor, characteristic, or measurement associated with theventilation of a patient, whether monitored by the ventilator or by anyother device. A ventilatory setting refers to any factor,characteristic, or measurement that is set by the ventilator and/oroperator. Sensors may further transmit collected data to the dataprocessing module 222 and, according to embodiments, the data processingmodule 222 may be configured to collect data regarding some ventilatoryparameters, to derive data regarding other ventilatory parameters, andto graphically represent collected and derived data to the clinicianand/or other modules of the ventilatory system 200. Some collected,derived, and/or graphically represented data may be indicative ofasynchrony. For example, data regarding expiratory time, exhaled tidalvolume, inspiratory time setting (T_(I)), etc., may be collected,derived, and/or graphically represented by data processing module 222.

Flow Data

For example, according to embodiments, data processing module 222 may beconfigured to monitor inspiratory and expiratory flow. Flow may bemeasured by any appropriate, internal or distributed device or sensorwithin the ventilatory system 200. As described above, flowmeters may beemployed by the ventilatory system 200 to detect circuit flow. However,any suitable device either known or developed in the future may be usedfor detecting airflow in the ventilatory circuit.

Data processing module 222 may be further configured to plot monitoredflow data graphically via any suitable means. For example, according toembodiments, flow data may be plotted versus time (flow waveform),versus volume (flow-volume loop), or versus any other suitable parameteras may be useful to a clinician. According to embodiments, flow may beplotted such that each breath may be independently identified. Further,flow may be plotted such that inspiratory flow and expiratory flow maybe independently identified, e.g., inspiratory flow may be representedin one color and expiratory flow may be represented in another color.According to additional embodiments, flow waveforms and flow-volumeloops, for example, may be represented alongside additional graphicalrepresentations, e.g., representations of volume, pressure, etc., suchthat clinicians may substantially simultaneously visualize a variety ofventilatory parameters associated with each breath.

As may be appreciated, flow decreases as resistance increases, making itmore difficult to pass gases into and out of the lungs (i.e.,F=P_(t)/R). For example, when a patient is intubated, i.e., havingeither an endotracheal or a tracheostomy tube in place, resistance maybe increased as a result of the smaller diameter of the tube over apatient's natural airway. In addition, increased resistance may beobserved in patients with obstructive disorders, such as COPD, asthma,etc. Higher resistance may necessitate, inter alia, a higher inspiratorytime setting (T_(I)) for delivering a prescribed pressure or volume ofgases, a higher flow setting for delivering prescribed pressure orvolume, a lower respiratory rate resulting in a higher expiratory time(T_(E)) for complete exhalation of gases, etc.

Specifically, changes in flow may be detected by evaluating various flowdata. For example, by evaluating FV loops, as described above, anincrease in resistance may be detected over a number of breaths. Thatis, upon comparing consecutive FV loops, the expiratory plot for each FVloop may reflect a progressive reduction in expiratory flow (i.e., asmaller FV loop), indicative of increasing resistance.

Pressure Data

According to embodiments, data processing module 222 may be configuredto monitor pressure. Pressure may be measured by any appropriate,internal or distributed device or sensor within the ventilatory system200. For example, pressure may be monitored by proximalelectromechanical transducers connected near the airway opening (e.g.,on the inspiratory limb, expiratory limb, at the patient interface,etc.). Alternatively, pressure may be monitored distally, at or near thelungs and/or diaphragm of the patient.

For example, P_(Peak) and/or P_(Plat) (estimating P_(a)) may be measuredproximally (e.g., at or near the airway opening) via single-pointpressure measurements. According to embodiments, P_(Plat) (estimatingP_(a)) may be measured during an inspiratory pause maneuver (e.g.,expiratory and inspiratory valves are closed briefly at the end ofinspiration for measuring the P_(Plat) at zero flow). According to otherembodiments, circuit pressure may be measured during an expiratory pausemaneuver (e.g., expiratory and inspiratory valves are closed briefly atthe end of exhalation for measuring EEP at zero flow).

Data processing module 222 may be further configured to plot monitoredpressure data graphically via any suitable means. For example, accordingto embodiments, pressure data may be plotted versus time (pressurewaveform), versus volume (pressure-volume loop or PV loop), or versusany other suitable parameter as may be useful to a clinician. Accordingto embodiments, pressure may be plotted such that each breath may beindependently identified. Further, pressure may be plotted such thatinspiratory pressure and expiratory pressure may be independentlyidentified, e.g., inspiratory pressure may be represented in one colorand expiratory pressure may be represented in another color. Accordingto additional embodiments, pressure waveforms and PV loops, for example,may be represented alongside additional graphical representations, e.g.,representations of volume, flow, etc., such that a clinician maysubstantially simultaneously visualize a variety of parametersassociated with each breath.

According to embodiments, PV loops may provide useful clinical anddiagnostic information to clinicians regarding the respiratoryresistance or compliance of a patient. Specifically, upon comparing PVloops from successive breaths, an increase in resistance may be detectedwhen successive PV loops shorten and widen over time. That is, atconstant pressure, less volume is delivered to the lungs when resistanceis increasing, resulting in a shorter, wider PV loop. According toalternative embodiments, a PV loop may provide a visual representation,in the area between the inspiratory plot of pressure vs. volume and theexpiratory plot of pressure vs. volume, which is indicative ofrespiratory compliance. Further, PV loops may be compared to one anotherto determine whether compliance has changed. Additionally oralternatively, optimal compliance may be determined. That is, optimalcompliance may correspond to the dynamic compliance determined from a PVloop during a recruitment maneuver, for example.

According to additional embodiments, PV curves may be used to compareC_(S) and C_(D) over a number of breaths. For example, a first PV curvemay be plotted for C_(S) (based on P_(Plat) less EEP) and a second PVcurve may be plotted for C_(D) (based on P_(Peak) less EEP). Undernormal conditions, C_(S) and C_(D) curves may be very similar, with theC_(D) curve mimicking the C_(S) curve but shifted to the right (i.e.,plotted at higher pressure). However, in some cases the C_(D) curve mayflatten out and shift to the right relative to the C_(S) curve. Thisgraphical representation may illustrate increasing P_(t), and thusincreasing R, which may be due to mucous plugging or bronchospasm, forexample. In other cases, both the C_(D) curve and the C_(S) curves mayflatten out and shift to the right. This graphical representation mayillustrate an increase in P_(Peak) and P_(Plat), without an increase inP_(t), and thus may implicate a decrease in lung compliance, which maybe due to tension pneumothorax, atelectasis, pulmonary edema, pneumonia,bronchial intubation, etc.

As may be further appreciated, relationships between resistance, staticcompliance, dynamic compliance, and various pressure readings may giveindications of patient condition. For example, when C_(S) increases,C_(D) increases and, similarly, when R increases, C_(D) increases.Additionally, as discussed previously, P_(t) represents the differencein pressure attributable to resistive forces over elastic forces. Thus,where P_(Peak) and P_(t) are increasing with constant V_(T) delivery, Ris increasing (i.e., where P_(Peak) is increasing without a concomitantincrease in P_(Plat)). Where P_(t) is roughly constant, but whereP_(Peak) and P_(Plat) are increasing with a constant V_(T) delivery,C_(S) is increasing.

Volume Data

According to embodiments, data processing module 222 may be configuredto derive volume via any suitable means. For example, as describedabove, during volume ventilation, a prescribed V_(T) may be set fordelivery to the patient. The actual volume delivered may be derived bymonitoring the inspiratory flow over time (i.e., V=F*T). Stateddifferently, integration of flow over time will yield volume. Accordingto embodiments, V_(T) is completely delivered upon reaching T_(I).Similarly, the expiratory flow may be monitored such that expired tidalvolume (V_(TE)) may be derived. That is, under ordinary conditions, uponreaching the T_(E), the prescribed V_(T) delivered should be completelyexhaled and FRC should be reached. However, under some conditions T_(E)is inadequate for complete exhalation and FRC is not reached.

Data processing module 222 may be further configured to plot derivedvolume data graphically via any suitable means. For example, accordingto embodiments, volume data may be plotted versus time (volumewaveform), versus flow (flow-volume loop or FV loop), or versus anyother suitable parameter as may be useful to a clinician. According toembodiments, volume may be plotted such that each breath may beindependently identified. Further, volume may be plotted such thatprescribed V_(T) and V_(TE) may be independently identified, e.g.,prescribed V_(T) may be represented in one color and V_(TE) may berepresented in another color. According to additional embodiments,volume waveforms and FV loops, for example, may be represented alongsideadditional graphical representations, e.g., representations of pressure,flow, etc., such that a clinician may substantially simultaneouslyvisualize a variety of parameters associated with each breath.

Disconnection of the Patient Ventilator Circuit

According to embodiments, data processing module 222 may be configuredto determine if the ventilation tubing system 130 or patient circuit hasbecome disconnected from the patient or the ventilator duringventilation. Data processing module 222 determines that a patientcircuit is disconnected by any suitable means. In some embodiments, dataprocessing module 222 determines that the patient circuit isdisconnected by evaluating data, such as exhaled pressure and/or exhaledvolume. In further embodiments, data processing module 222 determines ifthe patient circuit is disconnected by determining if a disconnect alarmhas been executed. A disconnect alarm is executed when the ventilationtubing system is disconnected from the patient and/or the ventilator. Ifthe disconnect alarm has been executed, then data processing module 222determines that the patient circuit is disconnected. If the disconnectalarm has not been executed, then data processing module 222 determinesthat the patient circuit is connected.

Breath Type

According to embodiments, data processing module 222 is configured toidentify the breath type. In some embodiments, data processing module222 is configured to identify the active trigger type utilized by thebreath type and/or the background trigger type utilized in thebackground. Data processing module 222 determines the breath type and/ortrigger type by any suitable systems or methods. In some embodiments,data processing module 222 determines the breath type and/or triggertype based on clinician or operator input and/or selection. In furtherembodiments, data processing module 222 determines the breath typeand/or trigger type based on ventilator selection of the breath typeand/or trigger type. For example, some breath types include VC, PC, VC+,PS, PA, IE Sync, DEA, TC, and VS.

Asynchrony Detection

A recent study suggests that clinicians are able to detect less thanone-third of patient efforts that do not result in the delivery of abreath, or missed breaths.¹ Further, this study has shown that the rateof correct detection decreases as the prevalence of missed breathsincreases. Considering that missed breaths may occur in up to 80% ofmechanically ventilated patients, systems and methods for betterdetection of asynchrony are needed. While operating a ventilator, it isdesirable to detect, limit, or preferably eliminate, asynchrony.¹Colombo, D., Cammarota, G., Alemani, M., Carenzo, L., Barra, F.,Vaschetto, R., et al. (2011). Efficacy of ventilator waveformsobservation in detecting patient-ventilator asynchrony. Critical CareMedicine, p. 3.

Accordingly, ventilator 202 may further include asynchrony module 224.Asynchrony is detected by the asynchrony module 224 when a missedbreath, false trigger, late trigger, early cycle, late cycle, doubletrigger, inadequate flow, and/or high tidal volume is detected. Asillustrated in FIG. 2B, the asynchrony module includes a missed breathdetection module 224 a, a false trigger detection module 224 c, a latetrigger detection module 224 d, an early cycle detection module 224 f, alate cycle detection module 224 g, a double trigger detection module 224e, an inadequate flow detection module 224 b, and/or a high tidal volumedetection module 224 i for detecting these various asynchronyconditions. In some embodiments, the detection of one type of asynchronycan cause or lead to the detection of another type of asynchrony. Theasynchrony module 224 receives and analyzes data gathered by or dataderived from data gathered by internal sensors 220 and/or distributedsensors 218. The asynchrony module 224 utilizes the received data incombination with data regarding detected triggers from an active and/orbackground trigger type.

Missed Breath Detection

Ventilator 202 may further include a missed breath detection module 224a. A missed breath, as used herein, is a patient inspiratory effort thatdoes not result in the delivery of a breath by the ventilator. A missedbreath occurs when the ventilator does not detect a patient inspiratoryand/or expiratory effort. The ventilator may not detect the inspiratoryand/or expiratory effort because the trigger threshold is set too highand/or because the inspiratory and/or expiratory effort is below theminimum trigger detection level for the active trigger type.Accordingly, missed breaths can lead to patient discomfort, patientfatigue, and/or extended ventilation time.

The type of triggering detection utilized by the ventilator isdetermined by the selected trigger type. Accordingly, different triggertypes will detect patient inspiratory and/or expiratory efforts ortriggers/cycles differently. Accordingly, the missed breath detectionmodule 224 a determines missed breaths by monitoring for patientinspiratory and/or expiratory efforts or patient triggers/cycles with anactive trigger type and with a background trigger type. If a firstpatient effort detected by the background trigger type correlates to asecond patient effort detected by the active trigger type, then thedetected patient efforts are considered to have been generated by thesame patient effort and a missed breath is not detected. The firstpatient effort and the second patient effort may correlate if recordedat the same time or within a reasonable and expected time delay, such as400 milliseconds (ms) or less for a neonate and 1 second or less for anadult. The amount of time varies based on the patient's PBW, the type ofventilator utilized, and the set trigger type. For example, the timevaries based on whether an adult, child, neonate, male, or female isbeing ventilated by the ventilator. Accordingly, the time delay listedabove is exemplary only and will vary based on the patient, ventilator,and/or trigger type. As discussed above, any inspiratory patient effortdetected by the active trigger type results in the delivery of a breath.

In some embodiments, the missed breath detection module 224 a detects amissed breath when a first detected patient effort by the backgroundtrigger type does not correlate with a detected patient effort by theactive trigger type. As discussed above, the first patient effort andthe second patient effort may correlate if recorded at the same time orwithin a reasonable and expected time delay, such as 400 ms or less fora neonate and 1 second or less for an adult. If the detected inspiratorypatient efforts by the background trigger type and the active triggertype do not correlate, then a missed breath is detected. In anembodiment, an equation or mathematical operation is used to determineif the first detected patient effort correlates with the second detectedpatient effort. In some embodiments, the active trigger type is utilizedduring a VC, VS, VC+, PS, PC, PA, TC, DEA, or IE Sync breath type. Insome embodiments, the active trigger type is a flow monitoring type, apressure monitoring type, a nasal detection type, an Edi type (or DEAtype), and/or a intrapleural pressure type (or IE Synch type). In otherembodiments, the background trigger type is a flow monitoring type, apressure monitoring type, a nasal detection type, an Edi type (or DEAtype), and/or a intraplueral pressure type (or IE Sync type).

In further embodiments, the missed breath detection module 224 a detectsa missed breath when an inspiratory patient effort and an expiratorypatient effort are detected by a background trigger type before aninspiratory patient effort is detected by the active trigger type. Asdiscussed above, any inspiratory patient effort detected by the activetrigger type results in the delivery of a breath.

In further embodiments, the missed breath detection module 224 adetermines a missed breath when an expiratory patient effort and patientinspiratory patient effort is detected by a background trigger typebefore an expiratory patient effort is detected by the active triggertype. As discussed above, any expiratory patient effort detected by theactive trigger type results in the delivery of expiration.

In other embodiments, the missed breath detection module 224 adetermines the number of missed breaths (also known as a missed breathmetric) by utilizing at least one counter. During these embodiments, theventilator updates a counter with a sum of the detected patientinspiratory and/or expiratory efforts by the background trigger type anda sum of the detected patient inspiratory and/or expiratory efforts bythe active trigger type. In these embodiments, the counter subtracts anypatient inspiratory and/or expiratory efforts determined by the activetrigger type and adds any patient efforts determined by the backgroundtrigger type in the counter to determine the number of missed breaths.In some embodiments, the number of missed breaths is referred to as amissed breath metric. In another embodiment a mathematical model oralgorithm is used to calculate how patient inspiratory and/or expiratoryefforts are detected with the background and active trigger type toupdate at least one counter. In an embodiment, the at least one counteris reset after a predetermined amount of time or breaths, or in responseto clinician input.

In another embodiment, at least two counters are used. In an embodimentwith at least two counters, the first counter is updated with a sum ofthe detected patient inspiratory and/or expiratory efforts by thebackground trigger type and a second counter is updated with a sum ofthe detected patient inspiratory and/or expiratory efforts by the activetrigger types. In embodiments with at least two counters, the missedbreath detection module 224 a performs an algorithm or mathematicaloperation, such as subtracting the count of the second counter from thecount of the first counter to calculate the number of missed breaths ora missed breaths metric. In some embodiments, the value of a counterrepresents a missed breath metric and no further algorithm ormathematical operation is needed to calculate the missed breaths metric.The number of missed breaths or the missed breaths metric may becalculated according to any suitable method.

False Trigger Detection

Ventilator 202 may further include a false trigger detection module 224c. A false trigger, as used herein, occurs when the ventilator deliversinspiration prior to the detection of a patient inspiratory effort by abackground trigger type. As used herein the term “prior” refers to anevent that occurs more than 5 ms before a referenced event. The falsetrigger may be from some anomalous condition that is interpreted by theventilator breath type as an inspiratory patient effort. Because of theshort expiratory time, the false trigger and early delivered inspirationmay come before the patient has the chance to fully exhale and may causegas-trapping in the lungs. Accordingly, false triggering can lead topatient discomfort and/or an increase in the length of ventilation time.

As discussed above, the type of triggering detection utilized by theventilator is determined by the selected trigger type. Accordingly,different trigger types will detect patient inspiratory efforts ortriggers differently. Therefore, the false trigger detection module 224c determines false triggers by monitoring for patient inspiratoryefforts or patient triggers with an active trigger type and with abackground trigger type. If a first patient effort detected by thebackground trigger type is within 60 milliseconds for a neonate and 100ms for an adult before a second patient effort is detected by the activetrigger type, then the detected patient efforts are considered to havebeen generated by the same patient effort and close enough to each otherto be a reasonable time delay so a false trigger is not detected.However, this threshold may vary based on the patient, trigger type, andtype of ventilator utilized. Accordingly, in some embodiments, if afirst patient effort detected by the background trigger type is within10 ms, 20 ms, 30 ms, 40 ms, 50 ms, 70 ms, 80 ms, 90 ms, 110 ms, 120 ms,130 ms, 140 ms, 150 ms, 160 ms, 170 ms, 180 ms, 190 ms, or 200 ms beforea second patient effort is detected by the active trigger type, then thedetected patient efforts are considered to have been generated by thesame patient effort and close enough to each other to be a reasonabletime delay so a false trigger is not detected. Alternatively, if a firstpatient effort detected by the background trigger type is more than 60milliseconds for a neonate and 100 ms for an adult before the secondpatient effort is detected by the active trigger type, then the detectedpatient efforts are considered to have been generated by the samepatient effort and far enough away from each other to not be considereda reasonable time delay so a false trigger is detected. In someembodiments, the active trigger type is utilized during a VC, VS, VC+,PS, PC, PA, TC, DEA, or IE Sync breath type. In some embodiments, theactive trigger type is a flow monitoring type, a pressure monitoringtype, a nasal detection type, an Edi type (or DEA type), and/or aintraplueral pressure type (or IE Synch type). In other embodiments, thebackground trigger type is a flow monitoring type, a pressure monitoringtype, a nasal detection type, an Edi type (or DEA type), and/or aintraplueral pressure type (or IE Sync type).

In other embodiments, the false trigger detection module 224 cdetermines the number of false triggers (also referred to as a falsetrigger metric) by utilizing at least one counter. During theseembodiments, the ventilator updates at least one counter every time afalse trigger is detected. In some embodiments, the at least one counteris reset after a predetermined amount of time, after a predeterminednumber of breaths, or in response to clinician input.

Late Trigger Detection

Ventilator 202 may further include a late trigger detection module 224d. A late trigger, as used herein, occurs when the ventilator deliversinspiration after the detection of a patient inspiratory effort by thebackground trigger type. As used herein the term “after” refers to anevent that occurs more than 5 ms after a referenced event. The latetrigger may occur when the trigger threshold is set too high. Therefore,the trigger may not be detected at the initial inspiratory effort andinstead is not detected until a continuation of the patient'sinspiratory effort reaches above the set threshold. Because of the longexpiratory time, the next breaths may come after the patient desires thebreath. Accordingly, a late trigger can lead to patient discomfort,patient fatigue, hypercapnia, and/or hypoxemia.

As discussed above, the type of triggering detection utilized by theventilator is determined by the selected trigger type. Accordingly,different trigger types will detect patient inspiratory efforts ortriggers differently. Therefore, the late trigger detection module 224 ddetermines false triggers by monitoring for patient inspiratory effortsor patient triggers with an active trigger type and with a backgroundtrigger type. If a first patient effort detected by the backgroundtrigger type is within 60 milliseconds for a neonate and 100 ms for anadult after a second patient effort is detected by the active triggertype, then the detected patient efforts are considered to have beengenerated by the same patient effort and close enough to each other tobe a reasonable time delay so a late trigger is not detected. However,this threshold may vary based on the patient, trigger type, and type ofventilator utilized. Accordingly, in some embodiments, if a firstpatient effort detected by the background trigger type is within 10 ms,20 ms, 30 ms, 40 ms, or 50 ms, 70 ms, 80 ms, 90 ms, 110 ms, 120 ms, 130ms, 140 ms, 150 ms, 160 ms, 170 ms, 180 ms, 190 ms, or 200 ms after asecond patient effort is detected by the active trigger type, then thedetected patient efforts are considered to have been generated by thesame patient effort and close enough to each other to be a reasonabletime delay so a late trigger is not detected. As discussed above, anyinspiratory patient effort detected by the active trigger type resultsin the delivery of inspiration. However, if a first patient effortdetected by the background trigger type is more than 60 milliseconds fora neonate and 100 ms for an adult after the second patient effort isdetected by the active trigger type, then the detected patient effortsare considered to have been generated by the same patient effort and farenough from each other to not be a reasonable time delay so a latetrigger is detected. In some embodiments, the active trigger type isutilized during a VC, VS, VC+, PS, PC, PA, TC, DEA, or IE Sync breathtype. In some embodiments, the active trigger type is a flow monitoringtype, a pressure monitoring type, a nasal detection type, an Edi type(or DEA type), and/or a intraplueral pressure type (or IE Synch type).In other embodiments, the background trigger type is a flow monitoringtype, a pressure monitoring type, a nasal detection type, an Edi type(or DEA type), and/or a intraplueral pressure type (or IE Sync type).

In other embodiments, the late trigger detection module 224 d determinesthe number of late triggers (also referred to as a late trigger metric)by utilizing at least one counter. During these embodiments, theventilator updates at least one counter every time a late trigger isdetected. In some embodiments, the at least one counter is reset after apredetermined amount of time, after a predetermined number of breaths,or in response to clinician input.

In further embodiments, the late trigger detection module 224 a detectsa late trigger when an inspiratory patient effort is detected by abackground trigger type at least 60 ms for a neonate and 100 ms for anadult before an inspiratory patient effort is detected by the activetrigger type and before an expiratory patient effort is detected by thebackground trigger type. As discussed above, any inspiratory patienteffort detected by the active trigger type results in the delivery of abreath.

Early Cycle Detection

Ventilator 202 may further include an early cycle detection module 224f. An early cycle, as used herein, occurs when the ventilator deliversexpiration prior to the detection of a patient expiratory effort by thebackground trigger type. The early cycle may be from some anomalouscondition that is interpreted by the ventilator breath type as anexpiratory patient effort. Because of the short inspiratory time, theearly cycle and early delivered expiration may come before the patienthas the chance to fully inhale preventing the patient from receiving theamount of oxygen desired. Accordingly, an early cycle can lead topatient discomfort, patient fatigue, hypercapnia, and/or hypoxemia.

Similar systems and methods as describe above for trigger detection maybe utilized for cycle detection. The type of cycling detection utilizedby the ventilator is determined by the selected trigger type.Accordingly, different trigger types will detect patient expiratoryefforts or cycles differently. Therefore, the early cycle detectionmodule 224 f determines early cycles by monitoring for patientexpiratory efforts or patient triggers with an active trigger type andwith a background trigger type. If a first patient expiratory effortdetected by the background trigger type is within 60 milliseconds for aneonate and 100 ms for an adult before a second patient expiratoryeffort is detected by the active trigger type, then the detected patientefforts are considered to be close enough to each other to be areasonable time delay so an early cycle is not detected. However, thisthreshold may vary based on the patient, trigger type, and type ofventilator utilized. Accordingly, in some embodiments, if a firstexpiratory patient effort detected by the background trigger type iswithin 10 ms, 20 ms, 30 ms, 40 ms, or 50 ms, 70 ms, 80 ms, 90 ms, 110ms, 120 ms, 130 ms, 140 ms, 150 ms, 160 ms, 170 ms, 180 ms, 190 ms, or200 ms before a second expiratory patient effort is detected by theactive trigger type, then the detected patient efforts are considered tobe close enough to each other to be a reasonable time delay so an earlycycle is not detected. As discussed above, any expiratory patient effortdetected by the active trigger type results in the delivery ofexpiration. However, if a first expiratory patient effort detected bythe background trigger type is more than 60 milliseconds for a neonateand 100 ms for an adult before the second patient effort is detected bythe active trigger type, then the detected patient efforts areconsidered to have been generated by the same patient effort and anearly cycle is detected. In some embodiments, the active trigger type isutilized during a VC, VS, VC+, PS, PC, PA, TC, DEA, or IE Sync breathtype. In some embodiments, the active trigger type is a flow monitoringtype, a pressure monitoring type, a nasal detection type, an Edi type(or DEA type), and/or a intraplueral pressure type (or IE Synch type).In other embodiments, the background trigger type is a flow monitoringtype, a pressure monitoring type, a nasal detection type, an Edi type(or DEA type), and/or a intraplueral pressure type (or IE Sync type).

In other embodiments, the early cycle detection module 224 f determinesthe number of early cycles or an early cycle metric by utilizing atleast one counter. During these embodiments, the ventilator updates atleast one counter every time an early cycle is detected. In someembodiments, the at least one counter is reset before a predeterminedamount of time, before a predetermined number of breaths, or in responseto clinician input.

Late Cycle Detection

Ventilator 202 may further include a late cycle detection module 224 g.A late cycle, as used herein, occurs when the ventilator deliversexpiration after the detection of a patient expiratory effort by abackground trigger type. The late cycle may occur when the cyclethreshold is set too high. Therefore, the cycle may not be detected atthe initial expiratory effort and instead is not detected until acontinuation of the patient's expiratory effort reaches above the setthreshold. Because of the long inspiratory time or low E_(SENS), thepatient may inhale too much gas causing gas-trapping in the lungs.Accordingly, late cycling can lead to patient discomfort.

Similar systems and methods as describe above for trigger detection maybe utilized for cycle detection. The type of cycling detection utilizedby the ventilator is determined by the selected trigger type.Accordingly, different trigger types will detect patient expiratoryefforts or cycles differently. Therefore, the late cycle detectionmodule 224 g determines late cycles by monitoring for patient expiratoryefforts or patient cycles with an active trigger type and with abackground trigger type. If a first patient effort detected by thebackground trigger type is within 60 milliseconds for a neonate and 100ms for an adult after a second patient effort is detected by the activetrigger type, then the detected patient efforts are considered to havebeen generated by the same patient effort and to be close enough to eachother to be a reasonable time delay so a late cycle is not detected.However, this threshold may vary based on the patient, trigger type, andtype of ventilator utilized. Accordingly, in some embodiments, if afirst expiratory patient effort detected by the background trigger typeis within 10 ms, 20 ms, 30 ms, 40 ms, or 50 ms, 70 ms, 80 ms, 90 ms, 110ms, 120 ms, 130 ms, 140 ms, 150 ms, 160 ms, 170 ms, 180 ms, 190 ms, or200 ms after a second expiratory patient effort is detected by theactive trigger type, then the detected patient efforts are considered tohave been generated by the same patient effort and considered to beclose enough to each other to be a reasonable time delay so a late cycleis not detected. As discussed above, any expiratory patient effortdetected by the active trigger type results in the delivery ofexpiration. However, if a first patient effort detected by thebackground trigger type is more than 60 milliseconds for a neonate and100 ms for an adult after the second patient effort is detected by theactive trigger type, then the detected patient efforts are considered tohave been generated by the same patient effort and to be far enough fromeach other to not be a reasonable time delay so a late cycle isdetected. In some embodiments, the active trigger type is utilizedduring a VC, VS, VC+, PS, PC, PA, TC, DEA, or IE Sync breath type. Insome embodiments, the active trigger type is a flow monitoring type, apressure monitoring type, a nasal detection type, an Edi type (or DEAtype), and/or a intraplueral pressure type (or IE Synch type). In otherembodiments, the background trigger type is a flow monitoring type, apressure monitoring type, a nasal detection type, an Edi type (or DEAtype), and/or a intraplueral pressure type (or IE Sync type).

In further embodiments, the late cycle detection module 224 g determinesa late cycle when an expiratory patient effort is detected by abackground trigger type at least 60 ms for a neonate and 100 ms for anadult before an expiratory patient effort is detected by the activetrigger type and before an inspiratory patient effort is detected by thebackground trigger type. As discussed above, any expiratory patienteffort detected by the active trigger type results in the delivery ofexpiration.

In other embodiments, the late cycle detection module 224 g determinesthe number of late cycles or a late cycle metric by utilizing at leastone counter. During these embodiments, the ventilator updates at leastone counter every time a late cycle is detected. In some embodiments,the at least one counter is reset after a predetermined amount of time,after a predetermined number of breaths, or in response to clinicianinput.

In other embodiments, the late cycle detection module 224 g determines alate cycles or a long inspiration time. In embodiments, the late cycledetection module 224 g detects a late cycle when the long inspiratorytime is longer than a predetermined threshold, which is based on apatient's body weight or predicted body weight. For example, a normalinspiratory time for most adults is about 800 ms to 1000 ms. However,the appropriate inspiration time varies for neonates, children, becausetheir respiratory rates are considerably different from most normaladults. Accordingly, the predetermined threshold varies based on thepredicted body weight (or age) of the patient. For example, duringventilation of a neonate, the predetermined long inspiratory timethreshold is 500 ms. In some embodiments, during ventilation of a child,the predetermined long inspiratory time threshold is 750 ms. In someembodiments, the late cycle detection module 224 g detects a late cyclewhen the inspiratory time is 1000 ms or higher. In other embodiments,the late cycledetection module 224 g detects a late cycle when theinspiratory time is 500 ms or higher. In further embodiments, the latecycle detection module 224 g detects a late cycle when the inspiratorytime is at 750 ms or higher. In additional embodiments, the late cycledetection module 224 g detects a late cycle when the inspiratory time is850 ms or higher. In some embodiments, the late cycle detection module224 g detects a late cycle when the inspiratory time is 900 ms orhigher. In other embodiments, the late cycle detection module 224 gdetects a late cycle when the inspiratory time is 400 ms or higher. Inother embodiments, the late cycle detection module 224 g detects a latecycle when the inspiratory time is 700 ms or higher.

The thresholds listed above are just one example list of possibleconditions that could be used to indicate a long inspiration time andtherefore a late cycle. Any suitable list of conditions for determiningthe occurrence of a long inspiration time and late cycle may beutilized.

Double Trigger Detection

Double triggering is a term that refers to a set of instances in which aventilator delivers two breaths in response to what is, in fact, asingle patient effort. A double trigger occurs when the ventilatordelivers two or more ventilator cycles separated by a very shortexpiratory time, with at least one breath being triggered by thepatient. Typically, the first cycle is patient triggered and the secondbreath is triggered by either a continuation of the patient'sinspiratory effort or from some anomalous condition that is interpretedby the ventilator as a second patient effort. Because of the shortexpiratory time, the additional breaths may come before the patient hasthe chance to fully exhale and may cause gas-trapping in the lungs.Accordingly, double triggering can lead to patient discomfort and/or anincrease in the length of ventilation time.

According to some embodiments, double trigger detection module 224 e maydetect double triggering when a double trigger has occurred at leastthree times within the last 60 seconds. According to furtherembodiments, double trigger detection module 224 e may detect doubletriggering when more than 30% of the patient-initiated mandatory breathshave a double trigger within the last 180 seconds. According toadditional embodiments, double trigger detection module 224 e may detectdouble triggering when more than 10% of the patient-initiated mandatorybreaths have a double trigger within the last 60 seconds. The doubletrigger detection module 224 e may begin the evaluation at the beginningof each patient-initiated breath.

In some embodiments, double trigger detection module 224 e detects adouble trigger when one or more of the following conditions are met:

-   -   1. expiratory time for a patient-initiated mandatory breath is        less than 240 milliseconds (ms);    -   2. the exhaled tidal volume associated with the expiratory        period is less than 10% of the delivered tidal volume of the        prior inspiratory period;    -   3. no disconnect alarm is detected.        In further embodiments, condition number 1, listed above, may        refer to any suitable expiratory time threshold. For example, in        an alternative embodiment the expiratory time threshold is an        expiratory time of less than 230 ms, 220 ms, 210 ms, 200 ms, or        190 ms depending upon the type of ventilator, patient, breath        type, ventilator parameters, ventilator settings, and/or        ventilator modes, etc. Condition number 3 listed above, is        considered a “threshold” in the present disclosure and in the        listed claims. Further, the detection of any yes/no “condition”        is considered a “threshold” in the present disclosure and in the        listed claims. In an embodiment of the double triggering        detection system, all three of the above conditions must be        present for the double trigger detection module 224 e to detect        a double trigger.

In some embodiments, conditions 1 and 2 are detected by the ventilatorbased on the triggering of an active trigger type. In other embodiments,conditions 1 and 2 are detected by the ventilator based on thetriggering of a background trigger type. In alternative embodiments,conditions 1 and 2 are detected by the ventilator based on thetriggering of either an active trigger type or a background triggertype.

The three thresholds listed above are just one example list of possibleconditions that could be used to indicate double triggering. Anysuitable list of conditions for determining the occurrence of doubletriggering may be utilized. For example, other suitableconditions/thresholds that may be utilized to determine that doubletriggering is implicated include a determination that the patientcircuit has not become disconnected, an analysis of pressure duringexhalation, a comparison of the estimated patient's neural inspiratorytime to inspiratory time delivered by the ventilator, an analysis of endtidal carbon dioxide (ETCO₂), an analysis of volumetric carbon dioxide(VCO₂), a determination that the expired volume is less than 50% of thedelivered volume, a determination that monitored PEEP is a negativenumber for one second or less during the inspiratory effort, and ananalysis of a ratio of inspiratory to expiratory time (I:E ratio).

Inadequate Flow Detection

Ventilator 202 may further include an inadequate flow detection module224 b. Inadequate flow is detected when a patient is receiving less flowthan desired by the patient during ventilation. Inadequate flow occurswhen a flow rate is set too low, a peak flow rate is set too low, and/orthe flow pattern does not match that of the patient's effort.Accordingly, inadequate flow can lead to patient discomfort, patientfatigue, hypercapnia, and/or hypoxemia.

According to embodiments, inadequate flow occurs as a result of variouspatient conditions and/or inappropriate ventilator settings. Thus,according to embodiments, inadequate flow detection module 224 bevaluates various ventilatory parameter data and ventilatory settingsbased on one or more predetermined thresholds to detect the presence ofinadequate flow. For example, inadequate flow detection module 224 b mayevaluate circuit pressure, mean airway pressure, etc., and may comparethe evaluated parameters to one or more predetermined thresholds. Inorder to prevent unnecessary alarms, prompts, notifications, and/orrecommendations, thresholds and conditions are utilized by theinadequate flow detection module 224 b to determine when inadequate flowhas occurred with sufficient frequency to warrant notification of theoperator. For example, in some embodiments, an inadequate flow thatoccurs in one breath in isolation from any other breaths with aninadequate flow will not be considered enough to warrant an occurrenceof inadequate flow by the inadequate flow detection module 224 b. Asused herein any threshold, condition, setting, parameter, and/orfrequency that are “predetermined” may be input or selected by theoperator and/or may be set or selected by the ventilator.

In embodiments, the inadequate flow detection module 224 b detects aninadequate flow when one or more predetermined thresholds are breachedat a predetermined frequency. In some embodiments, the inadequate flowdetection module 224 b detects an inadequate flow when one or morepredetermined thresholds are breached at least three times within apredetermined amount of time. In alternative embodiments, the inadequateflow detection module 224 b detects an inadequate flow when one or morepredetermined thresholds are breached by more than 30% of the PIMbreaths within a predetermined amount of time. In some embodiments, theinadequate flow detection module 224 b detects an inadequate flow whenone or more predetermined thresholds are breached in more than 10% ofthe PIM breaths within a predetermined amount of time. The predeterminedamount of time may be any suitable range of time for determining if aninadequate flow has occurred, such as a time ranging from 30 seconds to240 seconds. The frequency thresholds disclosed above are exemplary anddo not limit the disclosure. Any suitable frequency threshold fordetermining that the patient is receiving an inadequate flow duringventilation may be utilized.

According to some embodiments, inadequate flow detection module 224 bdetects an inadequate flow when a mean airway pressure for a PIM breathis below the set PEEP. In some embodiments, the mean airway pressure iscompared to a predetermined pressure. For example, the predeterminedpressure may be PEEP plus 1 cm H₂O, or PEEP minus 2 cm H₂O. The “meanairway pressure” referred to herein for a PIM breath is calculatedbetween the beginning of inspiration and a point where a predeterminedamount of tidal volume (e.g., 30%) has been delivered or a predeterminedproportion of the inspiration time has expired in the PIM breath.According to embodiments, inadequate flow detection module 224 b detectsan inadequate flow when more than three PIM breaths within the previous60 seconds exhibit a mean airway pressure for a PIM breath below the setPEEP and the expiratory time is greater than a predetermined amount oftime. According to further embodiments, inadequate flow detection module224 b detects an inadequate flow when more than 30% of the PIM breathswithin the previous 180 seconds exhibit a mean airway pressure for a PIMbreath below the set PEEP and the expiratory time is greater than apredetermined amount of time. In one embodiment, the inadequate flowdetection module 224 b begins the evaluation at the end of exhalationfor each PIM breath.

In some embodiments, inadequate flow detection module 224 b detects aninadequate flow when one or more of the following conditions are met forPIM breath:

-   -   1. the amount of pressure delivered when a predetermined amount        of tidal volume has been delivered or a predetermined proportion        of an inspiration time has expired in the PIM breath is less        than the set PEEP; and    -   2. the amount of mean airway pressure for the PIM breath is less        than the set PEEP.        Upon detecting one or more of the above conditions, the        inadequate flow detection module 224 b may also ensure that at        least one of the following two conditions is met:    -   3. expiratory time for a PIM breath is greater than a        predetermined amount of time;    -   4. the ventilation tubing system status is connected; and    -   5. no disconnect alarm is detected.

The confirmation conditions (3, 4, and 5) listed above confirm that theabove pressure conditions (1 and 2) are the result of an inadequateflow, instead of another underlying condition. For example, if adisconnect alarm or the tubing status is disconnected, then the abovepressure conditions (1 and 2) are the result of a disconnected patientcircuit and not the result of an inadequate flow. Accordingly, theventilator will not issue a prompt for inadequate flow if theseconditions are not met. In an alternative example, if the expiratorytime is less than a predetermined amount, then the above pressureconditions (1 and 2) are most likely the result of double triggering.Accordingly, the ventilator will not issue a prompt for inadequate flow,since the pressure condition was not caused by inadequate flow.

In further embodiments, condition number 3, listed above, refers to anysuitable expiratory time threshold. For example, in an alternativeembodiment the expiratory time threshold is an expiratory time ofgreater than 190 ms, 200 ms, 210 ms, 220 ms, 230 ms, or 250 ms dependingupon the type of ventilator, patient, breath type, ventilatorparameters, ventilator settings, and/or ventilator modes, etc. Infurther embodiments, the predetermined tidal volume, listed above,refers to any suitable amount of tidal volume during a PIM breath formeasuring pressure during ventilation to determine inadequate flowduring ventilation, such as 10%, 20%, 30%, 40% and 50%. In someembodiments, the predetermined proportion of the inspiration listedabove, refers to any suitable proportion of the inspiration time duringa PIM breath for measuring pressure during ventilation to determineinadequate flow during ventilation, such as 10%, 20%, 30%, 40% and 50%of the total amount of inspiration time. The ventilation tubing systemstatus is: (1) connected when the ventilation tubing system is connectedto the patient and the ventilator; and (2) disconnected when theventilation tubing system is not connected to the patient and/or theventilator. Condition number 4 and condition number 5 listed above, areconsidered a “threshold” in the present disclosure and in the listedclaims. Further, the detection of any yes/no “condition” is considered a“threshold” in the present disclosure and in the listed claims.

In some embodiments, conditions 1, 2, and 3 are detected by theventilator based on the triggering of an active trigger type. In otherembodiments, conditions 1, 2, and 3 are detected by the ventilator basedon the triggering of a background trigger type. In alternativeembodiments, conditions 1, 2, and 3 are detected by the ventilator basedon the triggering of either an active trigger type or a backgroundtrigger type.

The thresholds listed above are just one example list of possibleconditions that could be used to indicate an inadequate flow. Anysuitable list of conditions for determining the occurrence of aninadequate flow may be utilized. For example, other suitableconditions/thresholds that may be utilized to determine that aninadequate flow is implicated include a comparison of the patient flow(i.e., the flow at the connection to the patient) with the flowdelivered by the ventilator and a comparison of the pressure to apredetermined acceptable profile.

In other embodiments, the inadequate flow detection module 224 b detectsinadequate flow when there is a mismatch flow. A mismatch flow occurswhen a patient during a volume control ventilation attempts to pull moreflow than provided by the fixed flow rate during inspiration and changesthe delivered flow rate. The inadequate flow detection module 224 bdetects a mismatch flow when one or more predetermined thresholds arebreached at a predetermined frequency as discussed above. According tosome embodiments, inadequate flow detection module 224 b detects amismatch flow when a derivative of the pressure-time curve changes froma positive slope to a negative slope at a predetermined frequency. Insome embodiments, inadequate flow detection module 224 b detects amismatch flow when the derivative of the pressure-time curve for thepressure-time curve rises at a rate above a predetermined threshold atthe predetermined frequency. For example, the inadequate flow detectionmodule 224 b detects a mismatch flow when the pressure-time curve risesat a rate of at least 10 ml/m at the predetermined frequency. In someembodiments, the derivative of the pressure-time curve for thepressure-time curve rises at a rate of at least 50 ml/m at thepredetermined frequency. In further embodiments, the derivative of thepressure-time curve for the pressure-time curve rises at a rate of atleast 100 ml/m at the predetermined frequency.

In alternative embodiments, an inadequate flow is detected by detectinga change in a derivative of P_(m) exceeding a predetermined threshold ata predetermined frequency by a ventilator utilizing an active and/or abackground trigger type, such as IE Sync. In some embodiments, thepredetermined threshold is change of at least 30%. In alternativeembodiments, an inadequate flow is detected by detecting an increase inEdi exceeding a predetermined threshold at a predetermined frequency bya background trigger type, such as the DEA trigger type. In someembodiments, the predetermined threshold is an increase of Edi of atleast 15-20 microvolts. In some embodiments, both the IE Sync and theDEA trigger types are running in background to determine a flowmismatch.

According to embodiments, inadequate flow detection module 224 b detectsa flow mismatch when more than three PIM breaths within the previous 60seconds exhibit a change from a positive slope to a negative slope inthe derivative of the pressure-time curve, a rise in the derivative ofthe pressure-time curve that is above a predetermine threshold, a changein a derivative of P_(m) exceeding a predetermined threshold, and/or anincrease in Edi exceeding a predetermined threshold. According tofurther embodiments, inadequate flow detection module 224 b detects aflow mismatch when more than 30% of the PIM breaths within the previous180 seconds exhibit a change from a positive slope to a negative slopein the derivative of the pressure-time curve, a rise in the derivativeof the pressure-time curve that is above a predetermine threshold, achange in a derivative of P_(m) exceeding a predetermined thresholdand/or an increase in Edi exceeding a predetermined threshold. In oneembodiment, the inadequate flow detection module 224 b begins theevaluation at the end of exhalation for each PIM breath.

The thresholds listed above are just one example list of possibleconditions that could be used to indicate a flow mismatch, which causesan inadequate flow. Any suitable list of conditions for determining theoccurrence of a flow mismatch may be utilized. For example, othersuitable conditions/thresholds that may be utilized to determine that aflow mismatch is implicated include a comparison of the patient flow(i.e., the flow at the connection to the patient) with the flowdelivered by the ventilator and a comparison of the flow to apredetermined acceptable profile.

High Tidal Volume

Ventilator 202 may further include a high tidal volume detection module224 i. High tidal volume is caused by an inappropriate tidal volumesetting, by an inappropriate inspiratory pressure setting, and by missedbreaths and/or late triggers. Accordingly, a high tidal volume occurswhen a tidal volume is set too high, an inspiratory time is set toolong, and/or when the double triggers occur. Accordingly, a high tidalvolume can lead to patient discomfort, hyperinflation, and/orbarotrauma. However, a high tidal volume may occur as a result ofvarious patient conditions and/or inappropriate ventilator settings.Thus, according to embodiments, the high tidal volume detection module224 i evaluates various ventilatory parameter data and ventilatorysettings based on the detected patient efforts of an active and/orbackground trigger type and compares them to on one or morepredetermined thresholds to detect the presence of a high tidal volume.

In embodiments, the high tidal volume detection module 224 i detects ahigh tidal volume when the tidal volume is above a predeterminedthreshold, which is based on a patient's body weight or predicted bodyweight. For example, a normal tidal volume for most adults is about 4 to5 ml per kg. However, the appropriate tidal volume varies for neonates,children, and obese individuals because their weight is considerablydifferent from most normal adults. Accordingly, the predeterminedthreshold varies based on the weight of the patient. For example, duringventilation of a neonate, the predetermined tidal volume threshold is0.50 ml per kg or higher. In some embodiments, during ventilation of achild, the predetermine tidal volume threshold is 1 ml per kg or higher.In some embodiments, the high tidal volume detection module 224 idetects a high tidal volume when the tidal volume is at 6 ml per kg orhigher. In other embodiments, the high tidal volume detection module 224i detects a high tidal volume when the tidal volume is at 7 ml per kg orhigher. In further embodiments, the high tidal volume detection module224 i detects a high tidal volume when the tidal volume is at 8 ml perkg or higher. In additional embodiments, the high tidal volume detectionmodule 224 i detects a high tidal volume when the tidal volume is at 9ml per kg or higher. In some embodiments, the high tidal volumedetection module 224 i detects a high tidal volume when the tidal volumeis at 10 ml per kg or higher. In other embodiments, the high tidalvolume detection module 224 i detects a high tidal volume when the tidalvolume is at 11 ml per kg or higher. In other embodiments, the hightidal volume detection module 224 i detects a high tidal volume when thetidal volume is at 12 ml per kg or higher. In some embodiments, a tidalvolume of 12 ml per kg or higher occurs from stacked breaths based ondouble triggers.

The thresholds listed above are just one example list of possibleconditions that could be used to indicate a high tidal volume. Anysuitable list of conditions for determining the occurrence of a hightidal volume may be utilized.

Smart-Prompt Generation

Ventilator 202 may further include a prompt such as a smart promptmodule 226. As may be appreciated, multiple ventilatory parameters maybe monitored and evaluated in order to detect an implication ofasynchrony. In addition, when asynchrony is implicated, many cliniciansmay not be aware of adjustments to ventilatory parameters that mayreduce or eliminate asynchrony. As such, upon detection of asynchrony,the smart prompt module 226 may be configured to notify the clinicianthat asynchrony is implicated and/or to provide recommendations to theclinician for mitigating asynchrony. For example, smart prompt module226 may be configured to notify the clinician by displaying a smartprompt on display module 204 and/or within a window of the GUI.According to additional embodiments, the smart prompt is communicated toand/or displayed on a remote monitoring system communicatively coupledto ventilatory system 200. According to alternative embodiments, thesmart prompt is any audio and/or visual notification. Alternatively, inan automated embodiment, the smart prompt module 226 communicates with aventilator control system so that the recommendation may beautomatically implemented to mitigate asynchrony.

In order to accomplish the various aspects of the notification and/orrecommendation message display, the smart prompt module 226 maycommunicate with various other components and/or modules. For instance,smart prompt module 226 may be in communication with data processingmodule 222, asynchrony detection module 224, or any other suitablemodule or component of the ventilatory system 200. That is, smart promptmodule 226 may receive an indication that asynchrony has been implicatedby any suitable means. In addition, smart prompt module 226 may receiveinformation regarding one or more parameters that implicated thepresence of asynchrony and information regarding the patient'sventilatory settings and treatment. Further, according to someembodiments, the smart prompt module 226 may have access to a patient'sdiagnostic information (e.g., regarding whether the patient has ARDS,COPD, asthma, emphysema, or any other disease, disorder, or condition).

Smart prompt module 226 may further comprise additional modules formaking notifications and/or recommendations to a clinician regarding thepresence of asynchrony. For example, according to embodiments, smartprompt module 226 includes a notification module 228 and arecommendation module 230. For instance, smart prompts may be providedaccording to a hierarchical structure such that a notification messageand/or a recommendation message may be initially presented in summarizedform and, upon clinician selection, an additional detailed notificationand/or recommendation message may be displayed. According to alternativeembodiments, a notification message is initially presented and, uponclinician selection, a recommendation message may be displayed.Alternatively or additionally, the notification message may besimultaneously displayed with the recommendation message in any suitableformat or configuration.

Specifically, according to embodiments, the notification message alertsthe clinician as to the detection of a patient condition, a change inpatient condition, or an effectiveness of ventilatory treatment. Forexample, the notification message may alert the clinician thatasynchrony has been detected and the type of asynchrony detected. Thetype of asynchrony detected may include a missed breath, an early cycle,a flow mismatch, a late cycle, an false trigger, an inadequate flow, alate trigger, a high tidal volume, a double trigger, and a longinspiratory time. The notification message may further alert theclinician regarding the particular ventilatory parameter(s) thatimplicated asynchrony (e.g., low trigger sensitivity resulted in amissed breath, etc.)

Additionally, according to embodiments, the recommendation messageprovides various suggestions to the clinician for addressing a detectedcondition. That is, if asynchrony has been detected, the recommendationmessage may suggest that the clinician consider changing to a differentbreath type, such as IE Synch or DEA. According to additionalembodiments, the recommendation message may be based on the particularventilatory parameter(s) (e.g., expiratory sensitivity, electricalactivity of the diaphragm, tidal volume, etc.) that implicatedasynchrony. Additionally or alternatively, the recommendation messagemay be based on current ventilatory settings (e.g., breath type) suchthat suggestions are directed to a particular patient's treatment.Additionally or alternatively, the recommendation message may be basedon a diagnosis and/or other patient attributes. Further still, therecommendation message may include a primary recommendation message anda secondary recommendation message.

As described above, smart prompt module 226 may also be configured withnotification module 228 and recommendation module 230. The notificationmodule 228 may be in communication with data processing module 222,asynchrony detection module 224, or any other suitable module to receivean indication that asynchrony has been detected. Notification module 228may be responsible for generating a notification message via anysuitable means. For example, the notification message may be provided asa tab, banner, dialog box, or other similar type of display. Further,the notification messages may be provided along a border of thegraphical user interface, near an alarm display or bar, or in any othersuitable location. A shape and size of the notification message mayfurther be optimized for easy viewing with minimal interference to otherventilatory displays. The notification message may be further configuredwith a combination of icons and text such that the clinician may readilyidentify the message as a notification message.

The recommendation module 230 may be responsible for generating one ormore recommendation messages via any suitable means. The one or morerecommendation messages may provide suggestions and informationregarding addressing a detected condition and may be accessible from thenotification message. For example, the one or more recommendationmessages may identify the parameters that implicated the detectedcondition, may provide suggestions for adjusting one or more ventilatoryparameters to address the detected condition, may provide suggestionsfor checking ventilatory equipment or patient position, or may provideother helpful information. Specifically, the one or more recommendationmessages may provide suggestions and information regarding asynchrony.

According to embodiments, based on the particular parameters thatimplicated asynchrony, the recommendation module 230 providessuggestions for addressing asynchrony. In some embodiments, therecommendation module 230 provides suggestions for addressing asynchronybased on the type of asynchrony detected. That is, if asynchrony isimplicated, the one or more recommendation messages may includesuggestions or recommendations for the following:

switching to different breath type, such as PA, PS, IE Sync, DEA, TC,VC, VS, and etc.;

increasing or decreasing trigger sensitivity;

increasing or decreasing expiratory sensitivity;

changing the wave form or flow pattern;

changing tidal volume;

changing flow rate;

changing rise time;

changing inspiration time;

changing the inspiration pressure; and

any other suitable suggestion or recommendation.

According to still other embodiments, the recommendation messageincludes a primary message and a secondary message. That is, a primarymessage may provide notification of the condition detected and/orsuggestions that are specifically targeted to the detected conditionbased on the particular parameters that implicated the condition.Alternatively, the primary message may provide suggestions that mayprovide a higher likelihood of mitigating the detected condition. Thesecondary message may provide more general suggestions and/orinformation that may aid the clinician in further addressing and/ormitigating the detected condition. For example, the primary message mayprovide a specific suggestion for adjusting a particular parameter tomitigate the detected condition (e.g., consider increasing triggersensitivity). Alternatively, the secondary message may provide generalsuggestions for addressing the detected condition.

Additionally or alternatively, the one or more recommendation messagesmay also be based on a secondary condition or current ventilatorsettings for the patient and/or the type of asynchrony detected. Forexample, if asynchrony was implicated during a VC breath type bydetecting a missed breath, where the patient's current ventilatorsettings includes auto PEEP (also known as intrinsic PEEP or PEEPi),then the one or more recommendation messages may suggest that theclinician increase the set PEEP level. Further in this example, asecondary recommendation message may suggest if the tidal volume ishigh, decreasing the respiration rate or lowering the pressure/tidalvolume instead of changing the set PEEP level.

The detection of a missed breath, false trigger, late trigger, earlycycle, or late cycle in addition to auto PEEP as described above informsthe ventilator that the active breath type is not responding correctlyto patient efforts because of an improper PEEPi. Accordingly, in someembodiments, this information is utilized in a notification messageand/or recommendation message to the clinician (e.g., increase T_(I) bydecreasing E_(SENS)). In an alternative embodiment, the ventilatorautomatically adjusts the T_(I) based on the detected missed breath,false trigger, late trigger, early cycle, or late cycle and breach ofPEEPi.

TABLE 1 Recommendation messages based on breath type, secondaryconditions, detection method, and/or type of asynchrony detected.Secondary Primary Secondary Breath Detection Type of Condition and/orNotification Recommendation Recommendation Type Method AsynchronyVentilator Settings Message Message Message VC Monitoring InadequateDescending Asynchrony Consider Consider changing airway Flow ramp flowdetected increasing the to a pressure pressure pattern (inadequate flowrate and/or targeted breath (pressure flow changing the flow type suchas PA, signal detected) pattern to square PS, or PC. derivative) VCMonitoring Inadequate Flow Asynchrony Consider Consider changing airwayFlow pattern set detected increasing the to a pressure pressure tosquare (inadequate flow rate targeted breath (pressure flow type such asPA, signal detected) PS, or PC. derivative) VC IE Sync Missed No AutoAsynchrony Consider OR, consider monitoring as Breath PEEP and (missedincreasing trigger changing trigger a background inspiration breathssensitivity type trigger type time in detected) normal range based onPBW VC IE Sync Missed Auto PEEP Asynchrony Consider N/A monitoring asBreath and/or long (missed decreasing a background inspiration breathsinspiratory time trigger type time detected) VC IE Sync Missed Auto PEEPAsynchrony Consider OR consider monitoring as Breath (missed increasingPEEP decreasing a background breaths respiration rate trigger typedetected) and/or tidal volume VC IE Sync Late Trigger No Auto AsynchronyConsider OR, consider monitoring as PEEP and detected increasing triggerchanging trigger a background inspiration (late trigger sensitivity typetrigger type time in detected) normal range based on PBW VC IE Sync LateTrigger Auto PEEP Asynchrony Consider OR consider monitoring as and longdetected shortening decreasing tidal a background inspiration (latetrigger inspiratory time volume trigger type time detected) VC IE SyncLate Trigger Auto PEEP Asynchrony Consider OR consider monitoring asdetected increasing PEEP decreasing a background (late triggerrespiration and/or trigger type detected) tidal volume VC IE Sync Falsetrigger N/A Asynchrony Consider OR, consider monitoring as detecteddecreasing trigger changing trigger a background (false triggersensitivity type trigger type detected) VC IE Sync False trigger LeakAsynchrony Consider enabling N/A monitoring as present detected leakcompensation a background (false trigger trigger type detected) and leakcompensation monitoring VC IE Sync Double Tidal Asynchrony Consider N/Amonitoring as Trigger volume is detected increasing tidal a backgroundless than 6 (double volume to 7 trigger type mL/kg and trigger mL/kg or8 mL/kg and exhalation detected) exhalation time is time normalmonitoring VC IE Sync Double No Asynchrony Consider OR, considermonitoring as Trigger inadequate detected decreasing flow changing to aa background flow (double rate spontaneous trigger type, detectedtrigger breath type exhalation and detected) time inspirationmonitoring, time in and normal respiratory range rate based onmonitoring PBW and respiration rate VC IE Sync Long DescendingAsynchrony Consider OR, consider monitoring as Inspiration ramp flowdetected increasing flow changing the flow a background Time patter(long rate pattern to square trigger type inspiration time detected) VCIE Sync Long Square Asynchrony Consider N/A monitoring as Inspirationflow detected increasing flow a background Time pattern (long ratetrigger type inspiration time detected) PS IE Sync Late Cycle LeakAsynchrony Consider enabling OR, consider monitoring as present (latecycle leak compensation increasing a background detected) expirationtrigger type sensitivity and Leak compensation monitoring PS IE SyncEarly Cycle N/A Asynchrony Consider N/A monitoring as (early cycleincreasing a background detected) expiration trigger type sensitivityand/or inspiration time as a function of PBW monitoring PS MonitoringInadequate Low rise Asynchrony Consider N/A airway Flow time settingdetected increasing rise pressure (inadequate time (pressure flow signaldetected) derivative) PS IE Sync Missed Auto PEEP Asynchrony ConsiderN/A monitoring as Breath and long (missed increasing a backgroundinspiration breaths expiration trigger type time detected) sensitivityPS IE Sync Missed N/A Asynchrony Consider N/A monitoring as Breath(missed decreasing trigger a background breaths sensitivity trigger typedetected) PS IE Sync Missed High tidal Asynchrony Consider N/Amonitoring as Breath volume for (missed decreasing the a background PBWbreaths pressure support trigger type detected) setting PS IE SyncDouble High Asynchrony Consider N/A monitoring as Trigger expirationdetected decreasing a background sensitivity (double expiration triggertype trigger sensitivity detected) PS Monitoring Double High AsynchronyConsider N/A inspiration Trigger expiration detected decreasing time asa sensitivity (double expiration function of and short triggersensitivity PBW, exhalation detected) exhalation time time, andexhalation tidal volume, PC IE Sync Late Cycle N/A Asynchrony ConsiderOR, consider monitoring as (late cycle decreasing switching to a abackground detected) inspiration time spontaneous trigger type breathtype PC IE Sync Early Cycle N/A Asynchrony Consider OR, considermonitoring as (early cycle increasing switching to a a backgrounddetected) inspiration time spontaneous trigger type breath type PCMonitoring Inadequate Low rise Asynchrony Consider N/A airway Flow timesetting detected increasing rise pressure (inadequate time (pressureflow signal detected) derivative) PC IE Sync Missed No Auto AsynchronyConsider OR, consider monitoring as Breath PEEP and (missed increasingtrigger changing the a background inspiration breaths sensitivitytrigger type trigger type time is in detected) normal range based PBW PCIE Sync Missed Tidal Asynchrony Consider N/A monitoring as Breath Volume(missed decreasing a background too large breaths inspiration triggertype for PBW detected) pressure PC IE Sync Missed Auto AsynchronyConsider N/A monitoring as Breath PEEP, (missed decreasing a backgroundrespiration breaths inspiration time trigger type, rate, and detected)inspiration inspiration time time too monitoring, long for and PBWrespiration rate monitoring PC IE Sync Missed Auto PEEP AsynchronyConsider OR consider monitoring as Breath (missed increasing PEEPdecreasing a background breaths respiration rate if trigger typedetected) exhalation volume is high or consider decreasing inspirationtime PC IE Sync Double Inspiration Asynchrony Consider N/A monitoring asTrigger time is too detected increasing a background short for (doubleinspiration time trigger type PBW trigger and detected) respiration ratemonitoring TC IE Sync Late Cycle N/A Asynchrony Consider N/A monitoringas (late cycle increasing a background detected) expiration trigger typesensitivity TC IE Sync Early Cycle N/A Asynchrony Consider N/Amonitoring as (early cycle decreasing a background detected) expirationtrigger type sensitivity PA IE Sync Late Cycle N/A Asynchrony ConsiderOR, consider monitoring as (late cycle increasing decreasing support abackground detected) expiration setting if greater trigger typesensitivity than 80% PA IE Sync Early Cycle N/A Asynchrony Consider N/Amonitoring as (early cycle decreasing a background detected) expirationtrigger type sensitivity VC+ IE Sync Late Cycle N/A Asynchrony ConsiderOR, consider monitoring as (late cycle decreasing switching to a abackground detected) inspiration time spontaneous trigger type breathtype VC+ IE Sync Early Cycle N/A Asynchrony Consider OR, considermonitoring as (early cycle increasing switching to a a backgrounddetected) inspiration time spontaneous trigger type breath type VC+Monitoring Inadequate Low rise Asynchrony Consider N/A airway Flow timesetting detected increasing rise pressure (inadequate time (pressureflow signal detected) derivative) VC+ IE Sync Missed No Auto AsynchronyConsider OR, consider monitoring as Breath PEEP and (missed increasingtrigger changing the a background inspiration breaths sensitivitytrigger type trigger type time is in detected) normal range based PBWVC+ IE Sync Missed Tidal Asynchrony Consider N/A monitoring as BreathVolume (missed decreasing tidal a background too large breaths volumetrigger type for PBW detected) VC+ IE Sync Missed Auto AsynchronyConsider N/A monitoring as Breath PEEP, (missed decreasing a backgroundrespiration breaths inspiration time trigger type, rate, and detected)inspiration inspiration time time too monitoring, long for and PBWrespiration rate monitoring VC+ IE Sync Missed Auto PEEP AsynchronyConsider OR consider monitoring as Breath (missed increasing PEEPdecreasing a background breaths respiration rate if trigger typedetected) exhalation volume is high or consider decreasing inspirationtime VC+ IE Sync Double Inspiration Asynchrony Consider N/A monitoringas Trigger time is too detected increasing a background short for(double inspiration time trigger type PBW trigger and detected)respiration rate monitoring VS IE Sync Late Cycle Leak AsynchronyConsider enabling OR, consider monitoring as present (late cycle leakcompensation increasing a background detected) expiration trigger typesensitivity and Leak compensation monitoring VS IE Sync Early Cycle N/AAsynchrony Consider N/A monitoring as (early cycle increasing abackground detected) expiration trigger type sensitivity and/orinspiration time as a function of PBW monitoring VS MonitoringInadequate Low rise Asynchrony Consider N/A airway Flow time settingdetected increasing rise pressure (inadequate time (pressure flow signaldetected) derivative) VS IE Sync Missed Auto PEEP Asynchrony ConsiderN/A monitoring as Breath and long (missed increasing a backgroundinspiration breaths expiration trigger type time detected) sensitivityVS IE Sync Missed N/A Asynchrony Consider N/A monitoring as Breath(missed decreasing trigger a background breaths sensitivity trigger typedetected) VS IE Sync Missed High tidal Asynchrony Consider N/Amonitoring as Breath volume for (missed decreasing the a background PBWbreaths tidal volume trigger type detected) setting VS IE Sync DoubleHigh Asynchrony Consider N/A monitoring as Trigger expiration detecteddecreasing a background sensitivity (double expiration trigger typetrigger sensitivity detected) VS Monitoring Double High AsynchronyConsider N/A inspiration Trigger expiration detected decreasing time asa sensitivity (double expiration function of and short triggersensitivity PBW, exhalation detected) exhalation time time, andexhalation tidal volume,

Table 1 below lists various examples of primary and secondaryrecommendations for various breath types based on the listed additionalcurrent ventilator settings and/or on the type of asynchrony detected.

As noted above, according to embodiments, the notification message isassociated with a primary prompt and the one or more recommendationmessages may be associated with a secondary prompt. That is, a primaryprompt may provide an alert that asynchrony has been detected and mayfurther provide one or more potential causes for asynchrony.Alternatively, an alert may be separately provided, indicating thatasynchrony was detected, and the primary prompt may provide the one ormore potential causes for asynchrony. According to additional oralternative embodiments, the secondary prompt provides the one or morerecommendations and/or information that may aid the clinician in furtheraddressing and/or mitigating the detected condition. For example, thesecondary prompt may recommend addressing asynchrony by adjusting analternative parameter, by switching the breath type, and/or etc. Smartprompt module 226 may also be configured such that smart prompts(including alerts, primary prompts, and/or secondary prompts) may bedisplayed in a partially transparent window or format. The transparencymay allow for notification and/or recommendation messages to bedisplayed such that normal ventilator GUI and respiratory data may bevisualized behind the messages. This feature may be particularly usefulfor displaying detailed messages. As described previously, notificationand/or recommendation messages may be displayed in areas of the displayscreen that are either blank or that cause minimal distraction from therespiratory data and other graphical representations provided by theGUI. However, upon selective expansion of a message, respiratory dataand graphs may be at least partially obscured. As a result, translucentdisplay may provide the detailed message such that it is partiallytransparent. Thus, graphical and other data may be visible behind thedetailed alarm message.

Additionally, notification and/or recommendation messages may provideimmediate access to the display and/or settings screens associated withthe detected condition. For example, an associated parameter settingsscreen may be accessed from a notification and/or a recommendationmessage via a hyperlink such that the clinician may address the detectedcondition as necessary. An associated parameter display screen may alsobe accessed such that the clinician may view clinical data associatedwith the detected condition in the form of charts, graphs, or otherwise.That is, according to embodiments, the clinician accesses theventilatory data that implicated the detected condition for verificationpurposes. For example, when asynchrony has been implicated, depending onthe particular ventilatory parameters that implicated asynchrony, theclinician may be able to access ventilatory settings for addressingasynchrony (e.g., a settings screen for adjusting respiration rate,PEEP, E_(SENS), etc.) and/or to view associated ventilatory parametersthat implicated asynchrony (e.g., a graphics screen displayinghistorical flow waveforms, current tidal volume, and/or waveformsillustrating the asynchrony such as a missed breath or late trigger).

According to embodiments, upon viewing the notification and/orrecommendation messages, upon addressing the detected condition byadjusting one or more ventilatory settings or otherwise, or upon manualselection, the notification and/or recommendation messages are clearedfrom the graphical user interface. According to some embodiments, smartprompt module 226 clears the one or more messages from the graphicaluser interface if a setting is changed on the ventilator, such as aselected breath type. In further embodiments, smart prompt module 226clears the one or more messages from the graphical user interface if aventilator setting change was performed by the operator and a thresholdwas not breached for a predetermined amount of time or number ofbreaths. In further embodiments, smart prompt module 226 clears the oneor more messages from the graphical user interface if the thresholdbreach does not occur again during a predetermined amount of time orbreaths. In some embodiments, the smart prompt module 226 clears the oneor more messages from the graphical user interface upon user selection.

Asynchrony Detection During Ventilation of a Patient

FIG. 3 is a flow chart illustrating an embodiment of a method 300 fordetecting an implication of asynchrony.

As should be appreciated, the particular steps and methods describedherein are not exclusive and, as will be understood by those skilled inthe art, the particular ordering of steps as described herein is notintended to limit the method, e.g., steps may be performed in differingorder, additional steps may be performed, and disclosed steps may beexcluded without departing from the spirit of the present methods.

The illustrated embodiment of the method 300 depicts a method fordetecting asynchrony during ventilation of a patient. Method 300 beginswith collecting data operation 304. Collecting data operation 304 mayinclude receiving data regarding one or more ventilatory settingsassociated with ventilation of a patient. For example, the ventilatormay be configured to provide ventilation to a patient. As such, theventilatory settings and/or input received may include a prescribedV_(T), set flow (or peak flow), predicted or ideal body weight (PBW orIBW), E_(SENS), trigger sensitivity, PEEP, etc. Collecting dataoperation 304 may include receiving data from sensors regarding one ormore ventilatory parameters or receiving derived data from a processor.As discussed above, a ventilatory parameter refers to any factor,characteristic, or measurement associated with the ventilation of apatient, whether monitored by the ventilator or by any other device. Thecollected data may be transmitted by sensors. For example, dataregarding flow rate, circuit pressure, flow pattern, inspiratory timesetting (T_(I)), etc., may be collected from the sensors, operatorinterface, and/or processor.

At deliver ventilation operation 308, the ventilator providesventilation to a patient, as described above. That is, according toembodiments, the ventilator provides ventilation based on the set breathtype. For example, during a VC breath type in the mixed mode, theventilator provides ventilation based on a prescribed V_(T). In thisexample, the ventilator may deliver gases to the patient at a set flowat a set RR. When prescribed V_(T) has been delivered, the ventilatormay initiate the expiratory phase unless the ventilator detects apatient trigger or cycle.

While ventilation is being delivered, the ventilator may conduct variousdata processing operations. For example, at data processing operation310, the ventilator collects and/or derives various ventilatoryparameter data associated with ventilation of the patient based on abackground trigger type. For example, as described above, the ventilatormay collect data regarding parameters including T_(E), V_(T), T_(I),flow, pressure, etc. Additionally, the ventilator may derive variousventilatory parameter data based on the collected data, e.g.,IBW-predicted T_(I), volume, respiratory resistance, respiratorycompliance, detected patient triggers, detected patient cycles, etc. Asdescribed previously, measurements for respiratory resistance and/orcompliance may be trended continuously for a patient because ventilatorydata may be obtained without sedating the patient or otherwise.Additionally, the ventilator may generate various graphicalrepresentations of the collected and/or derived ventilatory parameterdata, e.g., flow waveforms, pressure waveforms, pressure-volume loops,flow-volume loops, etc.

According to some embodiments, at detect asynchrony operation 314 theventilator determines whether asynchrony is implicated by evaluating sexpiratory time, airway pressure, airway flow, delivered tidal volume,detected patient triggers, detected patient cycles, etc. and comparingthe evaluated parameters to one or more predetermined thresholds. Insome embodiments, in order to prevent unnecessary alarms, notifications,and/or recommendations, thresholds and conditions are utilized by thedetect asynchrony operation 314 to determine when asynchrony hasoccurred with sufficient frequency to warrant notification of theoperator. For example, in some embodiments, asynchrony that occurs inone breath in isolation from any other breath with asynchrony will notbe considered enough to warrant an occurrence of asynchrony by detectasynchrony operation 314.

In some embodiments, at detect asynchrony operation 314 the ventilatormay determine whether asynchrony is implicated based on a predeterminedfrequency of occurrence. For example, in one embodiment, the ventilatorat detect asynchrony operation 314 determines that asynchrony isimplicated when the number of detected inspiration patient efforts bythe background trigger type does not equal the number of deliveredbreaths by the active trigger type, when a detected patient effort(inspiration or expiration) is more than 60 ms away from thecorresponding delivered inspiration or expiration by the active triggertype, the pressure-time curve rises at a rate of at least 10 ml/m at thepredetermined frequency, detecting an increase in Edi exceeding apredetermined threshold at a predetermined frequency, when a derivativeof the pressure-time curve changes from a positive slope to a negativeslope at a predetermined frequency, when a change in a derivative ofP_(m) exceeds a predetermined threshold at the predetermined frequency,when inspiration time is too long based on a patient PBW, and/or whentidal volume is too high based on the patient PBW. For example, inanother embodiment, the ventilator at detect asynchrony operation 314determines that asynchrony is implicated when one or more of thefollowing conditions are met:

-   -   1. expiratory time for a patient-initiated mandatory breath is        less than 240 milliseconds (ms);    -   2. the exhaled tidal volume associated with the expiratory        period is less than 10% of the delivered tidal volume of the        prior inspiratory period;    -   3. no disconnect alarm is detected.

For example, in an additional embodiment, the ventilator at detectasynchrony operation 314 determines that asynchrony is implicated whenone or more of the following conditions are met for PIM breath:

-   -   1. the amount of pressure delivered when a predetermined amount        of tidal volume has been delivered or a predetermined proportion        of an inspiration time has expired in the PIM breath is less        than the set PEEP; and    -   2. the amount of mean airway pressure for the PIM breath is less        than the set PEEP.        Upon detecting one or more of the above conditions, the        ventilator may also ensure that at least one of the following        two conditions is met:    -   3. expiratory time for a PIM breath is greater than a        predetermined amount of time;    -   4. the ventilation tubing system status is connected; and    -   5. no disconnect alarm is detected.

If asynchrony is implicated, detect asynchrony operation 314 may proceedto issue smart prompt operation 316. If asynchrony is not implicated,the detect asynchrony operation 314 may return to collecting dataoperation 304. However, in some embodiments, the ventilator continuouslyperforms the collecting data operation 304, the deliver ventilationoperation 308, data processing operation 310, and detect asynchronyoperation 314.

The thresholds listed above are just one example list of possibleconditions that could be used to indicate asynchrony in the detectasynchrony operation 314. Any suitable list of conditions fordetermining the occurrence of asynchrony may be utilized by the detectasynchrony operation 314. As may be appreciated, the ventilator maydetermine whether asynchrony is implicated at detect asynchronyoperation 314 via any suitable means. Indeed, any of the above describedventilatory parameters may be evaluated according to various thresholdsfor detecting asynchrony. Further, the disclosure regarding specificventilatory parameters as they may implicate asynchrony is not intendedto be limiting. In fact, any suitable ventilatory parameter may bemonitored and evaluated for detecting asynchrony within the spirit ofthe present disclosure. As such, if asynchrony is implicated via anysuitable means, the detect asynchrony operation 314 may proceed to issuesmart prompt operation 316.

At issue smart prompt operation 316, the ventilator may alert theclinician via any suitable means that asynchrony has been implicated.For example, according to embodiments, the ventilator may display asmart prompt including a notification message and/or a recommendationmessage regarding the detection and/or cause of asynchrony on the GUI.According to alternative embodiments, the ventilator may communicate thesmart prompt, including the notification message and/or therecommendation message, to a remote monitoring system communicativelycoupled to the ventilator. According to alternative embodiments, theissued smart prompt is any visual and/or audio notification.

According to embodiments, the notification message may alert theclinician that asynchrony has been detected and, optionally, may provideinformation regarding the type of asynchrony and/or any ventilatoryparameter(s) that implicated asynchrony. According to additionalembodiments, the recommendation message may provide one or moresuggestions for mitigating asynchrony. According to further embodiments,the one or more suggestions may be based on the patient's particularventilatory settings (e.g. breath type, flow pattern, flow rate, etc.)and/or diagnosis. According to some embodiments, the clinician mayaccess one or more parameter settings and/or display screens from thesmart prompt via a hyperlink or otherwise for addressing asynchrony.According to additional or alternative embodiments, a clinician mayremotely access one or more parameter and/or display screens from thesmart prompt via a hyperlink or otherwise for remotely addressingasynchrony.

Smart Prompt Generation Regarding Asynchrony Detection

FIG. 4 is a flow chart illustrating an embodiment of a method 400 forissuing a smart prompt upon detecting an implication of asynchrony.

As should be appreciated, the particular steps and methods describedherein are not exclusive and, as will be understood by those skilled inthe art, the particular ordering of steps as described herein is notintended to limit the method, e.g., steps may be performed in differingorder, additional steps may be performed, and disclosed steps may beexcluded without departing from the spirit of the present methods.

The illustrated embodiment of the method 400 depicts a method forissuing a smart prompt upon detecting asynchrony during ventilation of apatient. Method 400 begins with detect operation 402, wherein theventilator detects that asynchrony is implicated based on a backgroundtrigger type, as described above in method 300.

At identify ventilatory parameters operation 404, the ventilator mayidentify one or more ventilatory parameters that implicated asynchrony.In some embodiments, in order to prevent unnecessary alarms,notifications, and/or recommendations, thresholds and conditions areutilized by identify ventilatory parameters operation 404 to determinewhen asynchrony has occurred with sufficient frequency to warrantnotification of the operator. For example, in some embodiments,asynchrony that occurs in a breath in isolation from any other breathwith asynchrony will not be considered enough to warrant an occurrenceof asynchrony by identify ventilatory parameters operation 404.

For example, the ventilator may recognize that asynchrony was implicatedwhen the number of detected inspiration patient efforts by thebackground trigger type does not equal the number of delivered breathsby the active trigger type, when a detected patient effort (inspirationor expiration) is more than 60 ms away from the corresponding deliveredinspiration or expiration by the active trigger type, the pressure-timecurve rises at a rate of at least 10 ml/m at the predeterminedfrequency, detecting an increase in Edi exceeding a predeterminedthreshold at a predetermined frequency, when a derivative of thepressure-time curve changes from a positive slope to a negative slope ata predetermined frequency, when a change in a derivative of P_(m)exceeds a predetermined threshold at the predetermined frequency, wheninspiration time is too long based on a patient PBW, and/or when tidalvolume is too high based on the patient PBW. For example, in anotherembodiment, the ventilator at detect asynchrony operation 314 determinesthat asynchrony is implicated when one or more of the followingconditions are met:

-   -   1. expiratory time for a patient-initiated mandatory breath is        less than 240 milliseconds (ms);    -   2. the exhaled tidal volume associated with the expiratory        period is less than 10% of the delivered tidal volume of the        prior inspiratory period;    -   3. no disconnect alarm is detected.        For example, in an additional embodiment, the ventilator at        detect asynchrony operation 314 determines that asynchrony is        implicated when one or more of the following conditions are met        for PIM breath:    -   1. the amount of pressure delivered when a predetermined amount        of tidal volume has been delivered or a predetermined proportion        of an inspiration time has expired in the PIM breath is less        than the set PEEP; and    -   2. the amount of mean airway pressure for the PIM breath is less        than the set PEEP.        Upon detecting one or more of the above conditions, the        ventilator may also ensure that at least one of the following        two conditions is met:    -   3. expiratory time for a PIM breath is greater than a        predetermined amount of time;    -   4. the ventilation tubing system status is connected; and    -   5. no disconnect alarm is detected.        The thresholds listed above are just one example list of        possible conditions that could be used to indicate asynchrony in        the parameters operation 404. Any suitable list of conditions        for determining the occurrence of asynchrony may be utilized by        the parameters operation 404. As may be appreciated, the        ventilator may use information regarding ventilatory parameters        that implicated asynchrony in determining an appropriate        notification and/or recommendation message of the smart prompt.        Based on the parameters that implicated the asynchrony, the        ventilator during the parameters operation 404 may further        identify the type of asynchrony detected, such as missed        breaths, late cycling, early cycling, inadequate flow, mismatch        flow, and etc.

At identify settings operation 406, the ventilator may identify one ormore current ventilatory settings associated with the ventilatorytreatment of the patient. For example, current ventilatory settings mayhave been received upon initiating ventilation for the patient and mayhave been determined by the clinician or otherwise (e.g., breath type,oxygenation, PBW or IBW, disease conditions, etc.). For instance,current ventilatory settings associated with ventilation for a patientmay include, V_(T), T_(I), flow, E_(SENS), flow pattern, IBW-predictedbased on T_(I), etc. As may be appreciated, the ventilator may useinformation regarding current ventilatory settings in determining anappropriate notification and/or recommendation message of the smartprompt.

At determine operation 410, the ventilator may determine an appropriatenotification message. For example, the appropriate notification messagemay alert the clinician that asynchrony has been implicated and,optionally, may provide information regarding the type of asynchrony andthe ventilatory parameter(s) that implicated asynchrony. For example,the appropriate notification may alert the clinician that asynchrony wasthe result of a missed breath as detected based on the monitoring ofpatient effort by the IE Sync background trigger type. In anotherexample, the appropriate notification may alert the clinician thatasynchrony was the result of a late trigger during ventilation with AutoPEEP. In another example, the appropriate notification may alert theclinician that asynchrony was implicated because a mean airway pressuredelivered is less than a set PEEP in more than 10% of the PIM breaths asdetected by an IE Sync background trigger type. For example, ifasynchrony was detected because of a missed breath, the ventilator mayoffer one or more notification messages that may include: “Considerincreasing trigger sensitivity” or “consider increasing E_(SENS).” Inalternative embodiments, measured parameters such as mean airwaypressure, detected patient efforts, and airway flow may be utilized asthe notification message.

At determine operation 412, the ventilator may determine an appropriateprimary recommendation message. The appropriate primary recommendationmessage may provide one or more specific suggestions for mitigatingasynchrony. According to some embodiments, in determining theappropriate primary recommendation message, the ventilator may take intoconsideration the one or more monitored ventilatory parameters thatimplicated asynchrony and the type of asynchrony detected.

According to other embodiments, in determining an appropriate primaryrecommendation message the ventilator may take into consideration one ormore of the patient's ventilatory settings. For example, if the breathtype is volume-control (VC), if the flow pattern is set to square, andif inadequate flow is the type of asynchrony detected, the ventilatormay offer one or more recommendation messages that may include:“Consider increasing the flow” or “Consider changing to a pressuretargeted breath type.” In another example, if the breath type isproportional assist (PA), and if the type of asynchrony detected is alate cycle, the ventilator may offer one or more recommendation messagesthat may include: “Consider increasing expiratory sensitivity.” Inanother example, if the breath type is pressure control (PC), if thetidal volume too large based on the patient PBW, and if the type ofasynchrony detected is a missed breath, the ventilator may offer one ormore recommendation messages that may include: “Consider decreasinginspiration pressure.” Any of the primary recommendations as discussedabove and as displayed in Table 1 above for any breath type may beutilized by method 400.

In some embodiments, at determine operation 414, the ventilator alsodetermines an appropriate secondary recommendation message. Thesecondary recommendation message may provide one or more generalsuggestions for mitigating asynchrony. For example, the secondaryrecommendation message may include: “Consider changing to a spontaneousbreath type, Consider changing to a pressure-based breath type; Considerchanging trigger type, Consider decreasing respiration rate if the tidalvolume is high” The secondary recommendation message may provideadditional recommendations for mitigating asynchrony. In furtherembodiments, the appropriate secondary recommendation message may takeinto consideration the patient's current ventilatory settings. That is,during a VC breath type, the ventilator may suggest changing to aspontaneous breath type such as PA, PS, IE Synch, DEA, or VS. As knownby a person of skill in the art any notification, message, and/orrecommendation disclosed herein may suitable for use as a primary and/orsecondary recommendation message.

At issue smart prompt operation 416, a smart prompt is issued. A smartprompt is issued when the ventilator alerts the clinician via anysuitable means that asynchrony has been implicated. For example,according to embodiments, a smart prompt may include an appropriatenotification message and an appropriate recommendation message regardingthe presence of asynchrony. Additionally or alternatively, the smartprompt may include an appropriate notification message, an appropriateprimary recommendation message, and an appropriate secondaryrecommendation message. The smart prompt may be displayed via anysuitable means, e.g., on the ventilator GUI and/or at a remotemonitoring station, such that the clinician is alerted as to thepotential presence of asynchrony and offered additional informationand/or recommendations for mitigating asynchrony, as described herein.

In some embodiments, a ventilatory system for issuing a smart promptwhen asynchrony is implicated during ventilation of a patient isdisclosed. The ventilatory system includes: means for collecting dataassociated with ventilatory parameters; means for processing thecollected ventilatory parameter data based on a background trigger type,wherein the step of processing the collected ventilatory parameter datacomprises deriving ventilatory parameter data from the collectedventilatory parameter data; means for determining that asynchrony isimplicated upon detecting that the processed ventilatory parameter databreaches a received at least one predetermined threshold; and means forissuing a smart prompt when asynchrony is implicated.

In some embodiments, a ventilatory system for issuing a smart promptwhen asynchrony is implicated during ventilation of a patient isdisclosed. The ventilatory system includes: means for detectingasynchrony based on a background trigger type, means for identifying oneor more ventilator parameters that implicated the asynchrony; means foridentifying the current ventilator settings, means for determining theappropriate notification message, means for determining the appropriateprimary recommendation message for the patient, means for determiningthe appropriate secondary recommendation for the patient, and means forissuing a smart prompt.

In further embodiments, the means for the medical ventilator areillustrated in FIGS. 1 and 2 and are described in the above descriptionsof FIGS. 1 and 2. However, the means described above for FIGS. 1 and 2and illustrated in FIGS. 1 and 2 are but one example only and are notmeant to be limiting.

Ventilator GUI Display of Initial Smart Prompt

FIG. 5 is an illustration of an embodiment of a graphical user interface500 displaying a smart prompt having a notification message 512.

Graphical user interface 500 may display various monitored and/orderived data to the clinician during ventilation of a patient. Inaddition, graphical user interface 500 may display various messages tothe clinician (e.g., alarm messages, etc.). Specifically, graphical userinterface 500 may display a smart prompt as described herein.

According to embodiments, the ventilator may monitor and evaluatevarious ventilatory parameters based on one or more predeterminedthresholds to detect asynchrony. As illustrated, a pressure waveform maybe generated and displayed by the ventilator on graphical user interface500. As further illustrated, the pressure waveform may be displayed suchthat pressure during inspiration 502 is represented in a different color(e.g., green) than pressure during expiration 504 (e.g., yellow). In oneembodiment, as illustrated, asynchrony 506 occurs when an IE Syncbackground trigger type detects more inspiration efforts than breathsdelivered by the VC breath type. Asynchrony results, in this case, whenthe patient desires more breaths than are being delivered by theventilator to the patient.

Upon a determination that asynchrony is implicated, the graphical userinterface 500 may display a smart prompt, e.g., smart prompt 510.

According to embodiments, smart prompt 510 may be displayed in anysuitable location such that a clinician may be alerted regarding adetected patient condition, but while allowing other ventilatorydisplays and data to be visualized substantially simultaneously. Asillustrated, smart prompt 510 is presented as a bar or banner across anupper region of the graphical user interface 500. However, as previouslynoted, smart prompt 510 may be displayed as a tab, icon, button, banner,bar, or any other suitable shape or form. Further, smart prompt 510 maybe displayed in any suitable location within the graphical userinterface 500. For example, smart prompt 510 may be located along anyborder region of the graphical user interface 500 (e.g., top, bottom, orside borders) (not shown), across an upper region (shown), or in anyother suitable location. Further, as described herein, smart prompt 510may be partially transparent (not shown) such that ventilatory displaysand data may be at least partially visible behind smart prompt 510.

Specifically, smart prompt 510 may alert the clinician that asynchronyhas been detected, for example by notification message 512. As describedherein, notification message 512 may alert the clinician that asynchronyis implicated via any suitable means, e.g., “Missed Breath Alert”(shown), “Asynchrony Alert” (not shown), “Asynchrony Detected” (notshown), “Asynchrony Implicated” (not shown), “Late Cycle Alert” (notshown), “Early Cycle Detected” (not shown), “Late Trigger Implicated”(not shown), “False trigger Alert” (not shown), “Inadequate FlowDetected” (not shown), “Mismatched Breath Implicated” (not shown), “LongInspiration Alert” (not shown), “Double Trigger Detected” (not shown),“Long Tidal Volume Implicated” (not shown), or etc. Smart prompt 510 mayfurther include information regarding ventilatory parameters thatimplicated asynchrony. For example, if asynchrony was detected based onmore inspiration efforts being detected by the background trigger typethan breaths delivered by the active trigger type, then this informationmay be displayed by the notification message 512 (e.g., “Moreinspiration patient efforts were detected by the IE Sync backgroundtrigger type than breath delivered by the active VC breath type,”shown). According to the illustrated embodiment, parameter information514 is provided along with the notification message 512 in a banner.According to alternative embodiments, in addition to the notificationmessage 512 and the parameter information 514, one or morerecommendation messages may be provided in an initial smart promptbanner (not shown). According to other embodiments, rather thanproviding information regarding ventilatory parameters that implicatedasynchrony in the initial smart prompt, this information may be providedwithin an expanded portion (not shown) of smart prompt 510.

According to embodiments, smart prompt 510 may be expanded to provideadditional information and/or recommendations to the clinician regardinga detected patient condition. For example, an expand icon 516 may beprovided within a suitable area of the smart prompt 510. According toembodiments, upon selection of the expand icon 516 via any suitablemeans, the clinician may optionally expand the smart prompt 510 toacquire additional information and/or recommendations for mitigating thedetected patient condition. According to further embodiments, smartprompt 510 may include links (not shown) to additional settings and/ordisplay screens of the graphical user interface 500 such that theclinician may easily and quickly mitigate and/or verify the detectedcondition.

As may be appreciated, the disclosed data, graphics, and smart promptillustrated in graphical user interface 500 may be arranged in anysuitable order or configuration such that information and alerts may becommunicated to the clinician in an efficient and orderly manner. Thedisclosed data, graphics, and smart prompt are not to be understood asan exclusive array, as any number of similar suitable elements may bedisplayed for the clinician within the spirit of the present disclosure.Further, the disclosed data, graphics, and smart prompt are not to beunderstood as a necessary array, as any number of the disclosed elementsmay be appropriately replaced by other suitable elements withoutdeparting from the spirit of the present disclosure. The illustratedembodiment of the graphical user interface 500 is provided as an exampleonly, including potentially useful information and alerts that may beprovided to the clinician to facilitate communication of detected setasynchrony in an orderly and informative way, as described herein.

Ventilator GUI Display of Expanded Smart Prompt

FIG. 6 is an illustration of an embodiment of a graphical user interface600 displaying an expanded smart prompt 606 having a notificationmessage and one or more recommendation messages 608.

Graphical user interface 600 may display various monitored and/orderived data to the clinician during ventilation of a patient. Inaddition, graphical user interface 600 may display an expanded smartprompt 606 including one or more recommendation messages 608 asdescribed herein.

According to embodiments, as described above, an expand icon 604 may beprovided within a suitable area of smart prompt 602. Upon selection ofthe expand icon 604, the clinician may optionally expand smart prompt602 to acquire additional information and/or recommendations formitigating the detected patient condition. For example, expanded smartprompt 606 may be provided upon selection of expand icon 604. Asdescribed above for smart prompt 510, expanded smart prompt 606 may bedisplayed as a tab, icon, button, banner, bar, or any other suitableshape or form. Further, expanded smart prompt 606 may be displayed inany suitable location within the graphical user interface 600. Forexample, expanded smart prompt 606 may be displayed below (shown) smartprompt 602, to a side (not shown) of smart prompt 602, or otherwiselogically associated with smart prompt 602. According to otherembodiments, an initial smart prompt may be hidden (not shown) upondisplaying expanded smart prompt 606. Expanded smart prompt 606 may alsobe partially transparent (not shown) such that ventilatory displays anddata may be at least partially visible behind expanded smart prompt 606.

According to embodiments, expanded smart prompt 606 may compriseadditional information (not shown) and/or one or more recommendationmessages 608 regarding detected asynchrony. For example, the one or morerecommendation messages 608 may include a primary recommendation messageand a secondary recommendation message. The primary recommendationmessage may provide one or more specific suggestions for mitigatingasynchrony. For example, if asynchrony was implicated duringpressure-control ventilation and if the type of asynchrony detected is alate cycle, then the ventilator may offer one or more primaryrecommendation messages 608 that may include: “Consider decreasinginspiration time.” The secondary recommendation message may provide oneor more general suggestions for mitigating asynchrony. For example, thesecondary recommendation message may include: “Consider changing tospontaneous breath type such as PA, PS, IE Sync, DEA, or VS.”

According to embodiments, expanded smart prompt 606 may also include oneor more hyperlinks 610, which may provide immediate access to thedisplay and/or settings screens associated with detected asynchrony. Forexample, associated parameter settings screens may be accessed fromexpanded smart prompt 606 via hyperlinks 610 such that the clinician mayaddress detected asynchrony by adjusting one or more parameter settingsas necessary. Alternatively, associated parameter display screens may beaccessed such that the clinician may view clinical data associated withasynchrony in the form of charts, graphs, or otherwise. That is,according to embodiments, the clinician may access the ventilatory datathat implicated asynchrony for verification purposes. For example, whenasynchrony has been implicated, depending on the particular ventilatoryparameters that implicated asynchrony, the clinician may be able toaccess associated parameter settings screens for addressing asynchrony(e.g., settings screens for adjusting flow pattern, peak flow rate,breath type, etc.). Additionally or alternatively, the clinician may beable to access and/or view display screens associated with theventilatory parameters that implicated asynchrony (e.g., a graphicsscreen displaying historical flow waveforms, volume waveforms, and/orpressure waveforms that give rise to implications of asynchrony).

As may be appreciated, the disclosed smart prompt and recommendationmessages 608 illustrated in graphical user interface 600 may be arrangedin any suitable order or configuration such that information and alertsmay be communicated to the clinician in an efficient and orderly manner.Indeed, the illustrated embodiment of the graphical user interface 600is provided as an example only, including potentially useful informationand recommendations that may be provided to the clinician to facilitatecommunication of suggestions for mitigating detected asynchrony in anorderly and informative way, as described herein.

Unless otherwise indicated, all numbers expressing measurements,dimensions, and so forth used in the specification and claims are to beunderstood as being modified in all instances by the term “about.”Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the present disclosure. Further, unlessotherwise stated, the term “about” shall expressly include “exactly,”consistent with the discussions regarding ranges and numerical data.Concentrations, amounts, and other numerical data may be expressed orpresented herein in a range format. It is to be understood that such arange format is used merely for convenience and brevity and thus shouldbe interpreted flexibly to include not only the numerical valuesexplicitly recited as the limits of the range, but also to include allthe individual numerical values or sub-ranges encompassed within thatrange as if each numerical value and sub-range is explicitly recited. Asan illustration, a numerical range of “about 4 percent to about 7percent” should be interpreted to include not only the explicitlyrecited values of about 4 percent to about 7 percent, but also includeindividual values and sub-ranges within the indicated range. Thus,included in this numerical range are individual values such as 4.5, 5.25and 6 and sub-ranges such as from 4-5, from 5-7, and from 5.5-6.5, etc.This same principle applies to ranges reciting only one numerical value.Furthermore, such an interpretation should apply regardless of thebreadth of the range or the characteristics being described.

It will be clear that the systems and methods described herein are welladapted to attain the ends and advantages mentioned as well as thoseinherent therein. Those skilled in the art will recognize that themethods and systems within this specification may be implemented in manymanners and as such is not to be limited by the foregoing exemplifiedembodiments and examples. In other words, functional elements beingperformed by a single or multiple components, in various combinations ofhardware and software, and individual functions can be distributed amongsoftware applications at either the client or server level. In thisregard, any number of the features of the different embodimentsdescribed herein may be combined into one single embodiment andalternative embodiments having fewer than or more than all of thefeatures herein described are possible.

While various embodiments have been described for purposes of thisdisclosure, various changes and modifications may be made which are wellwithin the scope of the present disclosure. Numerous other changes maybe made which will readily suggest themselves to those skilled in theart and which are encompassed in the spirit of the disclosure and asdefined in the appended claims.

1.-20. (canceled)
 21. A ventilator-implemented method for detecting andmitigating asynchrony during ventilation of a patient, the methodcomprising: collecting data associated with ventilatory parameters fromat least one sensor; processing the collected ventilatory parameterdata, wherein the step of processing the collected ventilatory parameterdata comprises deriving ventilatory parameter data from the collectedventilatory parameter data based at least on a background trigger type;determining that the asynchrony is implicated upon detecting that theprocessed ventilatory parameter data breaches a received at least onepredetermined threshold; and determining an appropriate ventilatoradjustment for mitigating the asynchrony; implementing the appropriateventilator adjustment for mitigating the asynchrony.
 22. The method ofclaim 21, wherein the step of determining asynchrony further requiresdetermining that the processed ventilatory parameter data breaches thereceived at least one predetermined threshold at a predeterminedfrequency.
 23. The method of claim 21, wherein the processed ventilatoryparameter data comprises: at least one of airway flow, airway pressure,and neural respiratory output, and wherein the processed ventilatoryparameter data comprises: at least one of a detected inspiratory triggerand a detected expiratory trigger.
 24. The method of claim 21, whereinthe background trigger type is an IE Sync trigger type.
 25. The methodof claim 21, wherein the step of determining that the asynchrony isimplicated comprises: receiving the at least one predeterminedthreshold, the at least one predetermined threshold comprising: a numberof first patient efforts detected by the background trigger type must beequal to a number of second patient efforts detected by an activetrigger type in a predetermined amount of time; determining the numberof first patient efforts detected by the background trigger type anddetermining the number of second patient efforts detected by the activetrigger type in the predetermined amount of time; and determining thatthe number of first patient efforts detected by the background triggertype is not equal to the number of second patient efforts detected bythe active trigger type in the predetermined amount of time.
 26. Themethod of claim 21, wherein the step of determining that the asynchronyis implicated comprises: receiving the at least one predeterminedthreshold, the at least one predetermined threshold comprising: a firstpatient effort detected by a background breath type must occur within 60milliseconds of a second patient effort detected by an active breathtype; determining when the first patient effort is detected by thebackground breath type and determining when the second patient effort isdetected by the active breath type; determining that the first patienteffort detected by the background breath type is more than 60milliseconds from the second patient effort detected by the activebreath type.
 27. The method of claim 21, wherein the step of determiningthat the asynchrony is implicated comprises: receiving the at least onepredetermined threshold, the at least one predetermined thresholdcomprising: a first inspiratory patient effort and an expiratory patienteffort is detected by the background trigger type before a secondinspiratory patient effort is detected by an active trigger type;determining when the first inspiratory patient effort and the expiratorypatient effort is detected by the background trigger type anddetermining when the second inspiratory patient effort is detected bythe active trigger type; determining that the first inspiratory patienteffort and the expiratory patient effort are detected by the backgroundtrigger type before a second patient effort is detected by the activetrigger type.
 28. The method of claim 21, further comprising: issuing amessage when the asynchrony is implicated; determining an appropriatenotification for the message based at least in part on a type ofasynchrony detected.
 29. The method of claim 21, further comprising:identifying one or more ventilatory settings associated with aventilatory treatment of the patient, wherein the appropriate ventilatoradjustment includes a change to the one or more ventilatory settings,and wherein the one or more ventilatory settings include at least one ofa breath type, an inspiration time, an exhalation time, an inspiratorysensitivity, an expiratory sensitivity, a flow rate, a rise time, a flowpattern, a tidal volume, and an inspiratory pressure.
 30. The method ofclaim 21, wherein determining the appropriate ventilator adjustment formitigating the asynchrony comprises: identifying a type of asynchronydetected, wherein the type of asynchrony is selected from a groupincluding: missed breath, early cycle, flow mismatch, late cycle, falsetrigger, inadequate flow, late trigger, high tidal volume, doubletrigger, and long inspiratory time.
 31. The method of claim 30, whereinthe appropriate ventilator adjustment comprises one of: a change to asquare flow pattern; a switch to a pressure-targeted breath type; anincrease in flow rate; an increase in trigger sensitivity; a change intrigger type; an increase in expiratory sensitivity; an increase in setPEEP; lower a set respiration rate; a decrease in trigger sensitivity;enable leak compensation; an increase in inspiration time; a decrease ininspiration time; a decrease in support setting; an increase in tidalvolume; a decrease in tidal volume; an increase in inspiration pressure;an increase in rise time; and a decrease in flow rate.
 32. A ventilatorysystem for adjusting ventilator settings to mitigate a detectedasynchrony during ventilation of a patient, comprising: at least oneprocessor; and at least one memory, communicatively coupled to the atleast one processor and containing instructions that, when executed bythe at least one processor cause the ventilator system to: collect dataassociated with ventilatory parameters from at least one sensor; processthe collected ventilator parameter data; detect that asynchrony isimplicated for the patient based on a background trigger type utilizingthe processed ventilator parameter data; determine an appropriatemessage when the asynchrony is implicated; and issue the appropriatemessage.
 33. The ventilatory system of claim 32, the instructionsfurther comprising: determine the processed ventilatory parameter datathat implicated the asynchrony, and wherein the determine theappropriate message is based at least in part on the processedventilatory parameter data that implicated the asynchrony.
 34. Theventilatory system of claim 32, wherein the appropriate message includesa notification that the asynchrony is implicated and informationregarding the processed ventilatory parameter data that implicated theasynchrony.
 35. The ventilatory system of claim 32, the instructionsfurther comprising: determine one or more ventilatory settingsassociated with a ventilatory treatment of the patient; and wherein thedetermine the appropriate message is based at least in part onevaluating the one or more ventilatory settings.
 36. The ventilatorysystem of claim 35, wherein the one or more ventilatory settings is abreath type.
 37. The ventilatory system of claim 32, wherein theappropriate message comprises at least one of: change to a square flowpattern; switch to a pressure-targeted breath type; increase in flowrate; increase in trigger sensitivity; change in trigger type; increasein expiratory sensitivity; increase in set PEEP; lower a set respirationrate; decrease in trigger sensitivity; enable leak compensation;increase in inspiration time; decrease in inspiration time; decrease insupport setting; increase in tidal volume; decrease in tidal volume;increase in inspiration pressure; increase in rise time; and decrease inflow rate.
 38. The ventilatory system of claim 32, wherein theappropriate message comprises at least one of: change to an IE Syncbreath trigger type; change to a DEA trigger type; change to an IE Syncbreath type; change to a DEA breath type; decrease in tidal volume;increase in expiration sensitivity; decrease in inspiration time;decrease in a support setting if greater than 80%; decrease inrespiration rate; decrease in respiration rate if exhalation volume ishigh; change to a spontaneous breath type; change to a flow pattern tosquare; change to a pressure targeted breath type; and change in triggertype.
 39. The ventilatory system of claim 32, wherein the determine theappropriate message comprises: determining if a secondary condition isimplicated; and identifying a type of asynchrony detected, wherein thetype of asynchrony is selected from a group including: missed breath,early cycle, flow mismatch, late cycle, false trigger, inadequate flow,late trigger, high tidal volume, double trigger, and long inspiratorytime.
 40. A ventilator system comprising: a pressure generating systemthat generates a flow of breathing gas; a ventilation tubing system thatdelivers the flow of breathing gas from the pressure generating systemto a patient; one or more sensors operatively coupled to at least one ofthe pressure generating system, the patient, and the ventilation tubingsystem, wherein the one or more sensors collect data associated withventilatory parameters; a data processing module, the data processingmodule processes the collected ventilatory parameter data based on abackground breath type; a ventilation module, the ventilation modulecontrols ventilation of the patient according to ventilator settings; anasynchrony detection module, the asynchrony detection module determinesthat an asynchrony is implicated upon detecting that the processedventilatory parameter data breaches a received at least onepredetermined threshold; and a smart prompt module, the smart promptmodule issues a message when the asynchrony is implicated.